Introduction
Throughout history, particularly from the High Middle Ages to the Early Modern period, various systems of intentional perforations are observed in helmet construction. Their interpretation depends largely on their placement and extent. Perforations located along the lower rim can be securely identified as attachment points for liners or padding (Schneider 1967). Theoretically, padding could be extended over the edge and stitched on both sides to blunt the sharp metal edge and reinforce the structure (Mödlinger 2018: 195). Holes located on the apex, sides, or nape – depending on the typology and configuration – may serve to secure liners, crests, or other heraldic decorations (Krause 2019: 49; Terjanian 2019: 116–8). In many cases, these functions are interchangeable and difficult to distinguish (Goll 2014: ref_arm_1461; Quasigroch 1979). Furthermore, certain large apertures on the frontal plate may have served to secure chains with toggles, allowing the helmet to be suspended when not in use (see Macků 2024: 63–7).
A distinct category consists of ventilation “breaths” or airholes (German: Atemlöcher) located in the frontal sections of the helmet. These were primarily designed to facilitate respiration within closed headpieces, while secondarily improving the wearer’s spatial vision. These breaths can be symmetrical or asymmetrical in arrangement. Most commonly, they appear as small circular holes arranged in a grid, though they may also form specific decorative motifs. Other documented shapes include triangular, narrow rectangular, and cruciform apertures (Capwell 2012: 11; Williams – Edge 2004). Large circular or rectangular openings, which would otherwise represent a significant safety risk in lethal combat, are a characteristic feature of specialized tournament helmets (Blair 1958: 197). Ventilation breaths are not exclusive to helmets, as they are also found on certain types of cuirasses (see Lazar et al. 2016).
Within the corpus of historical helmets, specific perforations located in the ear region appear, which were intended to improve sound reception (auditory holes, hearing holes; German: Gehörlöcher). In existing specialized literature, these are either grouped together with standard ventilation breaths or are given very little academic attention (e.g., Hrbatý 2006: 12–3; Impey 2022; Kalkman 2022: 126–7). Precisely due to this lack of scholarly discourse, the following text has been prepared for those interested in military history, arms production, and the experimental or sporting application of helmets.
Fig. 1: Example of ventilation breaths.
Source: Žákovský et al. 2012: Fig. 7.
Theoretical Framework
The transmission of information on the battlefield and the ability to maintain orientation within chaotic environments are fundamental prerequisites for effective command and the success of any modern military mission. In this dynamic context, Auditory Situational Awareness plays an indispensable role; it allows a soldier not only to localize threats outside their immediate field of vision but, more importantly, to receive and interpret tactical orders accurately in real time. Analysis of scholarly studies conducted using advanced military simulators clearly demonstrates that any disruption to speech intelligibility has detrimental consequences. Once communication intelligibility falls below a critical threshold of approximately 65–75%, there is a sharp increase in the cognitive load on the human brain. In such scenarios, the brain is forced to devote disproportionate effort to the mere decoding of words at the expense of environmental monitoring. This phenomenon results in increased reaction times, a higher incidence of fatal errors, and an overall reduction in battlefield survivability (see Mentel et al. 2013; Peters – Garinther 1990; Whitaker et al. 1990; 1993).
Current scientific and military research into ballistic, athletic, and protective headgear describes a persistent conflict between mechanical head protection and the preservation of Auditory Situational Awareness (Byrne – Kennedy 2022; Melzer et al. 2012; Scharine 2005; 2015; Vause – Grantham 1999; Zimpfer – Sarafian 2014). In modern helmets, the issue is not so much the moderation of volume as the distortion of high-frequency sounds. For the wearer, this results in an inability to distinguish whether a sound source is located in front of or behind them (so-called front-back confusion). This is primarily caused by the covering or shielding of the outer ear, which removes the subtle directional cues essential for spatial orientation. Research indicates that optimizing helmet geometry to leave the ears uncovered has a demonstrably positive effect on localization capabilities.
In current specialized literature, there is a lack of studies that exactly quantify the degree of auditory deterioration and the impact on Auditory Situational Awareness regarding historical helmets. To date, discussion of this issue has taken place almost exclusively through empirical observation within the historical reenactment community. However, the author’s twenty years of practical experience utilizing replicas of Early Medieval helmets suggests that without specific adaptations to the dome or padding, a degree of acoustic isolation occurs. The inability to identify commands and information from comrades leads to a reliance on visual orientation and, ultimately, a tendency toward individual actions rather than coordinated unit maneuvers. Given that modern research proves auditory limitations exist even in technologically advanced headgear, it can be reasonably assumed that this isolation represented a significant problem in pre-modern periods. Although metal head protection was for much of history the privilege of social elites, it is unlikely that diverse constructional approaches aimed at improving hearing – while maintaining maximum safety – would not have evolved over the centuries.
Historical Practice
The identification of auditory apertures is complicated by the fact that they can be analyzed almost exclusively in helmet types where the metallic components are long enough to cover the ears. Within this corpus, three primary design solutions emerge.
The first solution involves the creation of deep recesses or cutouts in the ear region. These may be rounded, following the anatomy of the ear, or relatively narrow and rectangular. This approach was popular in Classical and Roman-era helmets (see Bottini et al. 1988; Goldman 1966–1969) and saw a resurgence in popularity during the 15th century (Goll 2014: ref_arm_1995, 2050, 2137, 2154, 2163, 2204, 2205, 4421, 4437, 4445; Phyrr 2000: Cat. no. 8). Additional protection could be provided by the cheek-pieces and the neck-guard flanking the cutout on both sides.
Fig. 2: Helmets with ear cutouts.
Left: Classical helmet (Bottini et al. 1988: 283).
Right: Helmet from the second half of the 15th century; Metropolitan Museum of Art, New York, inv. no. 04.3.239.
An extension of the first approach involves cutouts at the rim of the dome coupled with partially recessed cheek-pieces. Typical examples are found throughout the Roman period. One variation is represented by the Wiesenau type, which features ear cutouts in the dome and corresponding recesses in the posterior section of the cheek-pieces (facing the nape). Protection against downward strikes is ensured by a protruding ear-guard. A second variation is found in Late Roman helmets of the Dunapentele/Intercisa and Deurne/Berkasovo types, where the aperture is located in the center of the cheek-piece (Klumbach 1973; Miks 2008; 2014). In the Deurne/Berkasovo type, these ear cutouts are shielded by non-ferrous covers, multi-point riveted to the dome, which are pierced with clusters of small circular or oval holes to facilitate hearing (Miks 2014: Fig. 33).
Fig. 3: Helmets with cutouts in the dome and cheek-pieces.
Left: Wiesenau type (Bottini et al. 1988: 336).
Right: Intercisa and Berkasovo types, alongside Berkasovo-type covers (Miks 2014: Figs. 24, 33).
The third solution involves perforating the metal elements of the helmet without creating large cutouts. In these cases, the metal is at most embossed into the shape of an ear or a raised surface to accommodate the outer ear. The simplest perforations are circular or oval and vary in size. Small, isolated circular holes are found on the cheek-pieces of certain Roman Niederbieber helmets (Bottini et al. 1988: 340) and on some 1st century masked helmets (Mitschke 2012). They also appear on bronze helmets from the Chinese Shang Dynasty (Varyonov 1984). A small central hole is present on the cheek-piece of a 16th–17th century Indian helmet (Mohamed 2008: 332, Cat. no. 319), while a significantly larger aperture is seen on the helmet from the Meskalamdug site, dating to approximately 2400 BCE (Borchhardt 1972: Pl. 19; Egg – Waurick 1990: Fig. 3).
Fig. 4: Helmet from Frankfurt-Heddernheim.
Left: General view of the helmet (Bottini et al. 1988: 340).
Right: Detail of the cheek-piece perforation (romancoins.info).
Fig. 5: Helmet from Nijmegen.
Left: General view of the helmet (Mitschke 2012: Fig. 1).
Right: Detail of the mask perforation (mijngelderland.nl).
Fig. 6: Helmet from Royal Tomb No. 1004, Xibeigang site.
Source: ndweb.iis.sinica.edu.tw.
Fig. 7: Helmet from the Meskalamdug site. Source: Borchhardt 1972: Pl. 19.
Large individual apertures can also take a heart-shaped form, as seen in 17th–18th century Hussar helmets, where the perforations are located in the center of the cheek-pieces (Żygulski 1975: Cat. nos. 154, 156–7, 162–5, 167–9).
Fig. 8: Hussar helmets. Source: Żygulski 1975: Cat. nos. 154, 157.
However, a significantly more numerous group of perforations consists of various clusters of small circular holes. These are primarily concentrated in the 14th–18th centuries, with Late Medieval helmets forming a minority compared to 16th–18th century examples. The clusters identified in this study can be summarized as follows:
- Triangular cluster of three holes: Depicted in a 14th century stained glass (cathedal Notre-Dame, Amiens). Documented on a 16th century helmet (Mohamed 2008: 318, Cat. no. 305).
- Cruciform arrangement of four holes without central hole: Observed on a 15th–16th century helmet (Metropolitan Museum of Art, inv. no. 29.150.1a; Paggiarino 2019: 130).
- Cruciform arrangement of four holes with a central hole: Identified in the 14th century (Blair 1958: 194–5), though this configuration gained significant popularity in 15th-century bascinets (Blair 1958: 194–5; 202–3) and other types throughout the 16th–18th centuries (Czajkowski et al. 2017: 145, Cat. no. 29; Hrbatý 2006: 37; Terjanian 2019: 170–2, 240–1; Żygulski 1975: Cat. no. 161).
- Circular cluster of five holes with a central hole: Documented on various 16th century helmet forms (Phyrr 2000: Cat. nos. 23, 25, 27).
- Circular cluster of six holes without a central hole: The sole recorded candidate is a 15th century sallet (Burges – de Cosson 1881: 499, Pl. 2.15).
- Circular cluster of six holes with a central hole: Recorded from the late 15th century (Terjanian 2019: 236–7), through the 16th (Grancsay 1938; Hrbatý 2006: 125; Krause 2022: 148), and into the 17th century (Phyrr 2000: Cat. no. 70).
- Circular cluster of eight holes with a central hole: Observed in both 16th century examples (Hrbatý 2006: 72, 80, 122; Krause 2022: 21, 25, 102; Paggiarino 2016: 294; Phyrr 2000: Cat. nos. 39, 54; Terjanian 2019: 255) and 17th century pieces (Czajkowski et al. 2017: 161, Cat. no. 39).
- Circular or oval cluster of ten holes without a central hole: Documented in the 17th century (Metropolitan Museum of Art, inv. no. 14.25.499).
- High-density circular clusters (10 to 21 holes) with central hole: Various complex configurations documented primarily in the 16th century (Phyrr 2000: Cat. nos. 28, 30; Czajkowski et al. 2017: 155, Cat. no. 35; Metropolitan Museum of Art, inv. no. 14.25.628).
- Square 9-hole grid: Observed in the 16th century (Terjanian 2019: 246).
- 7-hole grid: Recorded in the 16th century (Żygulski 1975: Cat. no. 105).
- 8-hole grid: Recorded in the 16th century (Krause 2022: 152).
- 12-hole grid: Documented in the 16th century (Alexander 2015: 92, Cat. no. 32).
- 13-hole grid: Observed in the 16th century (Krause 2022: 150–1).
Fig. 9: Selection of the most common helmet perforation patterns.
Fig. 10: Examples of perforation clusters on helmets from the 14th and 16th centuries.
Left: Metropolitan Museum of Art, New York, inv. no. 29.158.33.
Right: Metropolitan Museum of Art, New York, inv. no. 14.25.621; Phyrr 2000: Cat. no. 27.
Interpreting these clusters solely as auditory perforations may be an oversimplification. It is probable that they served multi-functional roles: improving hearing, increasing ventilation, and providing attachment points for decorations (feathers, horns, crests) when such ornaments were not fixed to the apex or nape.
Fig. 11: The collage on the left illustrates perforations not utilized for fixation of helmet decorations, while the image on the right shows various forms of decorations mounted to the sides of helmets.
Source: Krause 2019: 158; Terjanian 2019: Cat. nos. 42, 47, 50.
In addition to regularly organized circular perforations, we encounter haphazardly distributed holes. A prime example is a helmet bearing the mark of Lorenz Helmschmid from the 1480s, alongside analogous pictorial representations (Kirchhoff 2024: Figs. 79, 80). Archaeologists suggest that the large ear-region cutouts found on the helmet from Snettisham, England, may have been originally overlaid with perforated covers (Farley – Joy 2024: 270, Fig. 14.26).
Fig. 12: Helmets with irregular auditory perforations from the 1480s (Kirchhoff 2024: Figs. 79, 80).
Fig. 13: Illustrative reconstruction of the Snettisham helmet. Source: Farley – Joy 2024: Fig. 14.26.
Irregular perforations are further represented by atypical openwork featuring sharp edges, which precludes the attachment of any organic material and thus predisposes the aperture to functions such as ventilation or auditory enhancement. Notable examples include the pierced cheek-pieces of the Classical Agris helmet (Bottini et al. 1988: 298), the spiral openwork on a Chinese bronze helmet from the Eastern Zhou dynasty (Rogers 1996: Cat. no. 58), the intricately pierced cheek-pieces of 16th century Ottoman helmets (Alexander 2015: 95, Cat. no. 33; Żygulski 1975: Cat. no. 79), and the perforations found on large 15th–16th century tournament helmets (Kalkman 2022: 125; Krause 2022: 24; Terjanian 2019: 101–3, 111–2; see also Krause 2019: 49; Terjanian 2019: 207, Cat. no. 53).
Fig. 14: Examples of uncommon perforations.
Left: Chinese helmet from the Eastern Zhou Dynasty (Rogers 1996: Cat. no. 58).
Right: Ottoman helmet, 16th century (Alexander 2015: 96).
Auditory adaptations are evident not only in the metal shells but also in surviving liners. Remarkable examples – where the rear sections of the padding are separated from the front to create space for the ears – survive from late 15th and early 16th-century Germany and Austria. These were constructed from linen, tow, hemp, and leather thongs (Goll 2014: ref_arm_1638; Rimer et al. 2009: 134; Terjanian 2019: 103–4).
Fig. 15: Tournament helmet liners featuring ear openings.
Source: Goll 2014: ref_arm_1638; khm.at.
It is of significant interest that certain helmets from the first half of the 20th century feature strikingly similar cheek-piece perforations. These are primarily observed in early aviation and tank crew helmets, as well as racing and American football headgear. The apertures are typically configured either as a single large opening or organized into specific clusters: triads, quads, a circular arrangement of five holes with a central opening, a six-hole circle with a central opening, or an oval of eight holes with a central opening. Some cheek-pieces featuring a single large aperture are fitted with a brass disc, which may be plain or divided into four or eight segments (Zendri – Frizzera 2022: 264).
Fig. 16: Examples of perforated helmets from the first half of the 20th century.
From top left: 1910 Gamages model (vintageflyinghelmets.com); 1917 Roold model (mnm.webmuseo.com); 1918 Roold model (Zendri – Frizzera 2022: 264); 1916 Warren model (ima-usa.com); American football helmet, 1920s (mearsonlineauctions.com); Harley-Davidson, 1910s–1920s (le-zouave.com).
Discussion
In light of our research, the anatomical cutouts and perforations found in helmets cannot be reduced to mere elements intended solely for auditory optimization. These modifications served a multi-functional role; in addition to their acoustic function, they significantly facilitated thermoregulation and, in certain instances, served as anchor points for the fixation of chin straps or decorative elements. Consequently, these adaptations must be fundamentally understood as multi-purpose in nature, rather than exclusively as auditory improvements, as has occasionally been suggested (e.g., Burges – de Cosson 1881: 499). Multi-perforated clusters that cover a substantial surface area and follow the anatomy of the outer ear can be identified as being primarily intended for auditory enhancement. Conversely, solitary pairs of apertures most likely fulfilled a fastening or fixation function.
Unambiguously identifiable auditory adaptations integrated directly into the metallic components of helmets are prominent in two distinct historical epochs. They are relatively widespread in both European and Asian antiquity, reaching their highest frequency of occurrence during the Roman era. Following the collapse of the Western Roman Empire, these features largely vanished from the material culture. Despite an isolated case from the 14th century (Blair 1958: 194–5), lateral cutouts and perforations appear to have regained popularity only in the late 15th century, persisting into the modern era. Throughout the vast majority of the Middle Ages, these elements are absent (see Capwell 2015; 2021; 2022; 2025), even in helmet types that fully enclose the ears (Goll 2016; Strong 2018; Žákovský et al. 2012). The reasons for this prolonged absence constitute a complex problem requiring an interdisciplinary approach, offering a fertile field for both academic scholars and experimentators.
The absence of auditory adaptations in certain types of head protection can be partially explained by their inherent construction. Open-faced helmets, such as kettle hats, provided sufficient ventilation and acoustic transparency without the need for additional modifications (Gosk 2022). Regarding enclosed helmet types, it is plausible that extensive systems of ventilation breaths in the cheek area could have partially compensated for the function of specialized auditory holes (e.g., Price 2000: Fig. 17.2). Ultimately, helmet design represents a compromise between competing factors: protection, contemporary aesthetics, and specific functional requirements. The implementation of auditory adaptations can be interpreted as a prioritization of the wearer’s situational awareness. The ability to hear became a critical factor particularly during periods characterized by sophisticated tactics, complex maneuvering, and hierarchical command systems. Conversely, helmets lacking auditory adaptations may indicate a lower level of tactical interaction between combatants and a dominance of linear, less coordinated movements.
Note on Early Medieval Helmets (9th–12th Century)
In the context of the Early Middle Ages, metallic helmets represented an exceedingly costly protective element (see Vlasatý 2022: 105). Consequently, it is assumed that the majority of combat during this period occurred without metallic head protection, and any potential auditory adaptations would thus pertain to relatively rare artifacts accessible only to a small percentage of the population. Eleven Early Medieval European helmets from the 9th to 12th centuries – approximately one-tenth of the known corpus – are equipped with apertures along the rim of the dome in the ear region. These include examples from Kozel Castle (Macků – Pilná 2021), Trnčina (Shchedrina – Kainov 2021), a continental helmet in an Oxford museum (Vlasatý et al. 2024), Babruysk (Kainov – Marzaljuk 2024), the Brodivskyi District (Vlasatý 2020), Gorzuchy (Vlasatý 2022b), Giecz (Vlasatý 2024a), the Makarivskyi District (Papakin et al. 2017: № 18), Mokre (Vlasatý 2022c), Olszówka (Vlasatý 2022d), and Walric (Beard 1922; 1935). These apertures are circular, with a maximum diameter of approximately 0.5 cm; their configuration varies between symmetrical and asymmetrical, and they appear as both single holes and pairs. Some are situated in the center of the brow band, while others are positioned just above it.
Fig. 17: Helmet from the Kozel Castle collection. Source: Macků – Pilná 2021: Fig. 3.
To date, no definitive assessment of this phenomenon exists. It is certain that several apertures in helmets of the “Black Mound” type, which constitute the majority of the aforementioned examples, were originally filled with rivets in the position above the brow band (Babruysk, Gorzuchy, Giecz, Makarivskyi District, Mokre, Olszówka). This is evidenced by the rivets on helmets from Rajkoveckoe Gorodishche (Gončarov 1950: 97, Pl. XV.2–4), the banks of the Krasnodar Reservoir (Kirpičnikov 2009: Figs. 37–9), and photographs of the Babruysk helmet taken at the moment of discovery (Kainov – Marzaljuk 2024: Fig. 3.5). Given 13th–14th century analogies where such apertures are filled with omega-shaped loops for suspending mail (Gorbunov – Isupov 2002: Figs. 1–2; Maklasov et al. 2018: Figs. 1–2), and 12th–13th century iconography (Alekseychik – McSweeney 2021), it is probable that these apertures served to secure chin straps (Vlasatý 2024b).
However, the simple perforations observed in the Ancient helmets mentioned previously suggest that the possibility of some apertures functioning as auditory adaptations cannot be entirely dismissed. Nevertheless, this would represent an uncommon solution. Aside from certain Vendel Period helmets that combine cheek-pieces with metallic plates – and are thus well-suited for sound reception (Lindqvist 1931; Tweddle 1992: Fig. 539) – the dominant form of neck protection for Early Medieval helmets was the aventail made of mail. Mail offers an excellent combination of protection, ventilation, and acoustic permeability. If Early Medieval helmets were adapted for improved hearing at all, such adaptations most likely concerned the organic liner. This raises the question of whether Early Medieval aventails were lined. Evidence suggests they were, as seen in the 6th century boy’s grave in Cologne, where the mail was lined with a Coptic wool tapestry (Bender Jørgensen 1987; Walton Rogers 2007: 82–3). Another find from the Balyk-Sook site in the Altai (8th–9th century) shows an aventail lined and edged with silk (Kubarev 2011: 156). Other Early and High Medieval mail curtains have been found with fragments of leather (Gorelik 2017: Fig. 17) and linen (Shchedrina 2022: 83) corroded onto them. In any case, these linings appear to have been relatively thin, single-layered, and intended for comfort. If so, auditory adaptations may have been unnecessary, as a single layer of textile – as seen in 13th century iconography where mail coifs rest on simple caps (e.g., Morgan M.638, fol. 43v) – can be considered sufficiently breathable and acoustically permeable.
Fig. 18: Use of simple caps beneath mail coifs.
Source: Morgan M.638, fol. 43v.
Under the assumption that neck-guard linings were more robust, it would be theoretically possible to leave voids around the ears to create simple auditory vents. A pilot experiment conducted by Zdeněk Stárek using a Stromovka-type helmet (Stárek 2022) tested this hypothesis. Over fifteen years of use, the helmet proved functional, with the owner noting significant improvements in both acoustics and ventilation. As thick neck padding is standard in modern reenactment, such a modification is recommended, particularly when mail protection with robust lining encircles the entire helmet circumference rather than just the area from temple to temple.
Fig. 19: Experimental auditory perforations in a helmet liner.
Source: Stárek 2022.
Acknowledgements
The author wishes to express his sincere gratitude to Kryštof Šámal for providing the initial impetus for this study and for granting access to unique primary sources, without which it would have been impossible to address this subject in such extensive detail.
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