The procedures and formalities related to the public defence of doctoral dissertations have evolved in the course of several centuries. Today, faculties have different views as to the degree of formality of the public examination of dissertations. Some faculties observe old traditions, while others aim to create a seminar-like atmosphere with vivid discussion. The Custos appointed by the faculty acts as the official chair of the examination, so any details regarding the examination procedure should be agreed with him or her.