Usage has become blurred with time, but monks are properly members of the monastic orders, exempt from episcopal (diocesan) jurisdiction, normally constrained to reside in their monasteries. Their principal activity consisted in singing the divine office, divided into the canonical hours of matins, lauds, prime, terce, sext, none, vespers, and compline. The whole psalter filled a weekly cycle, but there were complex seasonal variations. In the middle ages the 'mendicant' orders of friars were founded, not constrained to reside in anyone house of their order but still exempt from diocesan jurisdiction. Later a large number of smaller 'congregations' were founded. By the sixteenth century many of the foundations had outlived their original purposes, without finding acceptable new social roles.