The mortarboard hat worn at graduation ceremonies across the English-speaking world is one of the few hat forms that has maintained nearly continuous institutional use for over 500 years. Most wearers have never been told why it looks the way it does, and the explanations given in graduation programmes (when they are given at all) are frequently incorrect. The hat's history is more interesting and more contested than the ceremonial context suggests.
What the Mortarboard Actually Is
The mortarboard is a square, flat-topped academic cap with a tassel hanging from a button at the center of the square board. The hat is worn with the board parallel to the ground (level) and the tassel hanging to one side. The board is typically attached to a close-fitting skull cap that holds it in position on the head.
Its name comes from the resemblance to a mortarboard used in bricklaying -- the flat square board with a central handle used by bricklayers to hold mortar during construction. The connection is purely visual and does not indicate any functional or historical relationship between the hat and construction trades.
Where the Square Hat Came From
The origin of the square academic cap is disputed among costume historians and academics, with three competing theories:
Theory 1: From the pileus quadratus -- a square cloth hat worn by Roman Catholic clergy in the medieval period. Universities in medieval Europe had strong clerical connections, and academic dress borrowed heavily from clerical dress. The pileus quadratus (which itself evolved into the biretta) may have become the academic square cap through this clerical-to-academic transfer.
Theory 2: From the biretta directly -- the biretta is a square-sided clerical cap worn by Roman Catholic clergy, typically with three ridges on the top surface and a pompom at the center. The biretta's square silhouette is directly related to the mortarboard's square board, and the historical connection between universities and the Church makes this a natural influence pathway.
Theory 3: From the book -- a less well-supported theory suggests that the square cap represents a book held flat, symbolising scholarship. This is sometimes repeated in graduation ceremonies but has limited historical documentation supporting it as the actual origin.
The Biretta and Its Academic Legacy
The biretta deserves its own description because it is a distinct hat that continues in active use in Roman Catholic clerical contexts and has strong visual relationship with academic dress. The biretta is a square-sided, rigid cap with three (or sometimes four) ridges projecting upward from the corners of the crown, and a pompom or tuft at the top center. The number and colour of the ridges, and the colour of the hat overall, indicates the wearer's rank: black for priests, purple for bishops, red for cardinals, white for the Pope.
The biretta's square profile -- seen from above, it is a square -- created the visual vocabulary that academic dress adopted and modified. The mortarboard is essentially a biretta with a flat board instead of three ridges, retaining the square geometry but simplifying the crown structure.
The Tudor Bonnet: The Alternative Academic Hat
Less well-known outside the United Kingdom, the Tudor bonnet is the academic cap worn for doctoral degrees at many British universities -- a round, soft velvet cap with a wide brim and no rigid square board. It looks substantially different from the mortarboard and represents a different historical lineage.
The Tudor bonnet's round form is associated with the round soft caps (pileus) of medieval scholarship, as distinguished from the square cap that became more standard for lower degree levels. Many British universities reserve the mortarboard for undergraduate and master's degrees and use the Tudor bonnet specifically for doctoral graduates.
The Tassel Tradition
The tassel hanging from the mortarboard's center button is one of the most symbolically loaded elements of the graduation ceremony. In American academic tradition, the tassel is moved from the right side of the cap to the left during the graduation ceremony to mark the transition from candidate to graduate. This is a 20th-century American ceremonial convention -- there is no medieval or Renaissance precedent for the tassel-turning ceremony, which appears to have developed in American academic tradition as a collective participation ritual rather than as a continuation of old tradition.
The tassel colour in American academic dress often indicates the wearer's academic field rather than their institution -- gold for science, white for arts, blue for education, and so on across a standardised field-to-colour mapping developed by the American Council of Education.
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Frequently Asked Questions
Which side does the tassel go on before and after graduation?
In American academic tradition, the tassel is worn on the right side before the degree is conferred and moved to the left after. This convention is specifically American and not universal -- at British, Australian, and many other institutions, there is no tassel-moving ceremony, and the tassel position has no symbolic significance. Within the American tradition, the exact moment of the move varies: at some institutions all graduates move their tassels simultaneously when the class is collectively conferred; at others, each graduate moves their own tassel when they receive their diploma on stage.
Why do doctoral graduates sometimes not wear mortarboards?
In many British university traditions, doctoral graduates wear the Tudor bonnet (the round velvet cap) rather than the mortarboard, which is reserved for lower degree levels. In American academic dress, doctoral graduates typically wear mortarboards but may also wear tam-style caps (larger, rounder, with more fabric in the crown) that distinguish them visually from bachelor's and master's candidates. The specific academic dress convention varies by institution, and most universities publish their academic dress regulations.
Is the mortarboard specific to English-speaking countries?
No, but it is most associated with academic tradition in English-speaking countries (UK, US, Canada, Australia, New Zealand) and in institutions influenced by British academic dress traditions. Continental European universities have different academic dress traditions that may not include the square cap at all, or may use it in modified forms. The biretta remains in use at Catholic institutions internationally. Academic dress conventions are institutional and national rather than universal, and a PhD graduate at a German, French, or Dutch university would have a very different graduation dress experience than at a comparable British or American institution.
What does the academic hood represent?
The academic hood worn with graduation gown and cap has a complex and now primarily decorative history. Hoods originated as functional garments (cloaks with hoods) worn by medieval scholars and clergy who were outdoors in cold, often unheated buildings. The hood became an accessory of academic rank -- different colour linings indicating different degrees and institutions. By the 19th century, the hood had become purely ceremonial and was worn as a formal element of academic dress rather than as weather protection. The colours of the hood's lining indicate the wearer's degree level and institution according to a complex system maintained by national academic dress associations.
