A Tudor bonnet (also referred to as a doctor's bonnet or round cap) is a traditional soft-crowned, round-brimmed cap, with a tassel hanging from a cord encircling the hat. As the name suggests, the Tudor bonnet was popularly worn in England and elsewhere during Tudor times (1485 and 1603).
Today the cap is strongly associated with academic tradition. It is typically worn as part of academic dress by the holder of a research or professional doctoral degree or a full higher doctorate. It may also be worn by a person who has been awarded an honorary doctorate. At certain educational establishments the cap distinguishes university officers, such as the esquire bedell, university marshal, the president of the students' union, and members of the university council.