This list provides a guide to the most important opera composers, as determined by their presence on a majority of compiled lists of significant opera composers. (See the "Lists Consulted" section for full details.) The composers run from Jacopo Peri, who wrote the first ever opera in late 16th century Italy, to John Adams, one of the leading figures in the contemporary operatic world. The brief accompanying notes offer an explanation as to why each composer has been considered major. Also included is a section about major women opera composers, compiled from the same lists. For an introduction to operatic history, see opera. The organisation of the list is by birthdate.