The kind of music heard in the Catholic Church was known as chant or plainchant, often known as “Gregorian chant” (after St Gregory the Great, who was Pope from 590-604). The text (the words that were sung) were the standard words of the liturgy. The words of the Mass were set to music by many composers. Music for the dead was called Requiem Mass. There was also music for Vespers and the Compline. Until the 16th century the organ was only used to accompany the singing. In the Renaissance period many great composers such as Giovanni da Palestrina and Orlande de Lassus wrote polyphonic music for the Catholic Church. They often wrote motets: short pieces based on texts which were not part of the liturgy.