The Mainzer Hoffest (literally "Mainz court festival") or Diet of Pentecost was a Hoftag (imperial diet) of the Holy Roman Empire started in Mainz on 20 May 1184.[1] It was organised by Emperor Frederick I on the island of Maaraue in front of Mainz in the mouth of the Main on the occasion of Pentecost. Due to its large number of visitors and its cultural pleasures, it represented a highlight of the knightly way of life and the development of power of the dynasty of Hohenstaufen.