In the early Middle Ages, with the Sekke-monzeki (temples headed by regents) and miya-monzeki (temples headed by imperial princes) systems being in place, cloistered imperial princes from Myoho-in Temple, Joren-in Temple and Sanzen-in Temple (the Tendai Three Monzeki) in particular began to assume the position of Tendai-zasu frequently.
中世になると、摂家門跡、宮門跡の制度が整えられ、とりわけ妙法院・青蓮院・三千院（天台三門跡）から法親王が、天台座主として就任することが多くなった。