Braun (Liturgische Gewandung, p. 513) thinks that the symbolism of the cross may have had some influence in fixing and propagating the square shape, and he quotes a decree of the synod of Aix (1585) ordering the J g h clergy to wear a biretta sewn in the form of a cross (biretum in modum crucis consuturn, ut ecclesiasticos homines decet).
So far as the legality of the use of the biretta in the Church of England is concerned, this was pronounced by Sir R.
With the extension of its use, too, the custom grew up (c. 1300) of investing clerks with the biretum as the symbol of the transfer of a benefice, a custom which survives, in Roman Catholic countries, in the solemn delivery of the red biretta by the head of the state to newly created cardinals, who afterwards go to Rome to receive the red hat.
The use of the Roman biretta has been introduced by a certain number of the clergy into the Anglican Church.
The introduction of the biretta in the 15th century tended to replace the use of the almuce as a head-covering, and the hood now became smaller, while the cape was enlarged till in some cases it fell below the elbows.
The priest came out with his purple velvet biretta on his head, adjusted his hair, and knelt down with an effort.
This red biretta is called the zucchetto.
Only in Spain has the biretta continued to be worn without the raised ridges.