orry, That's Not a Tricorne
by Sevrin Lord de Savage

misconception on when the tricorne hat was first introduced in Western Europe has arisen out of research based solely on a superficial visual interpretation of headgear found in historic portraits of notable clergymen. What appears at first glance to be a tricorne hat, is in fact a biretum or catercap (also known as a Canterbury cap).

A biretum (biretum, birettum, dim of birrus; Fr: barette; Eng: barret-cap) is a brimless cap worn by the catholic clergy from the 13th century onward. Prior to this era, the pileus (a skull cap) was the favoured headwear, with the name biretum at first being synonymous with the pileus. Over time, the style of the biretum evolved into the form that is still in use today.
Cardinal Reginald Pole
(1500-1558)
he biretum is square and stiff with three or four raised board-like arched ridges at times bearing a knob or tassel at the centre junction. The cap is covered with cloth or silk and its colour depends on the rank of the wearer; white for the Pope; red for Cardinals; purple for bishops; and black for the lower ranking clergy.

The variation found in England was the Canterbury cap, later known as the catercap, which was of a softer form with four protruding peaks and a raised seam across the top forming the shape of the cross. Seen from the front and worn slightly back on the head - as in the portraits of Cardinals Pole and Sadoleto to the right - the catercap appears to only have three points, the one on the back not being obvious.
Cardinal Jacopo Sadoleto
(1477-1547)
he tricorne hat (or tri-cornered or three-cornered hat) was a wide brimmed hat usually black in colour that was pinned to the sides and back to form a triangular shape unlike the square biretum or catercap. The tricorne came into popular fashion very late in the 17th century and falling out of favour shortly before the French Revolution.

So, no - the tricorne hat did not exist within the time period mandated by the Society for Creative Anachronism.
The actual construction of
the biretum or catercap
can be seen in this mid-
16th century portait of an
unknown Cardinal