In the annals of Bulgarian monasteries, events and facts are intertwined from the history of the Bulgarian state, linked to the spiritual maturing of the Bulgarians, the formation of their national identity and culture. Established mainly in the time of the First and Second Bulgarian Kingdoms, the Holy Cloisters were centres for the reassertion and dissemination of Christianity in the Bulgarian lands, especially in the first years after the conversion to Christianity in 864. Literary schools functioned in them, which made a major contribution to the development of the Bulgarian literacy, of literature and education. Invaluable translated and original works were created, and the murals, iconostases and exquisite church utensils are among the masterpieces of the Bulgarian artistic and applied arts. During the Revival period, monastery schools were founded, revolutionary committees were established, the monks took an active part in the national liberation struggle.