Feast days. Wednesdays and Fridays were fast days, except the interval between Easter and Whit Sunday. The food allowed was barley bread, milk, fish, and eggs. Flesh meat was not allowed except on great feasts. In Ireland, a distinctive form of penance developed, where confession was made privately to a priest, under the seal of secrecy, and where penance was given privately and ordinarily performed privately as well. Penance was considered therapeutic rather than punitive. Certain handbooks were made, called "penitentials", designed as a guide for confessors and as a means of regularising the penance given for each particular sin. According to Thomas Pollock Oakley, the penitential guides first developed in Wales, probably at St. David's, and spread by missions to Ireland. Irish monasticism maintained the model of a monastic community while, like John Cassian, marking the contemplative life of the hermit as the highest form of monasticism. Saints' lives frequently tell of monks (and abbots) departing some distance from the monastery to live in isolation from the community. Irish monastic rules specify a stern life of prayer and discipline in which prayer, poverty, and obedience are the central themes. Irish monks needed to learn Latin, the language of the Church. Thus they read Latin texts, both spiritual and secular, with an enthusiasm that their contemporaries on the continent lacked. Subjects taught included Latin, Greek, Hebrew, grammar, rhetoric, poetry, arithmetic, chronology, the Holy Places, hymns, sermons, natural science, history and especially the interpretation of Sacred Scripture. In 544 St Ciarán founded a monastery at Clonmacnoise, which became one of the most important centers of learning and religious life in Ireland. Contrary to common practice, the title of abbot which included the title "Comarba of Saint Ciarán" at the community was not hereditary, which reflected the humble origins of its founder. In 557 St Brendan founded a monastery at Clonfert. By the end of the seventh century, Irish monastic schools were attracting students from England and from Europe. The achievements of insular art, in illuminated manuscripts like the Book of Kells, high crosses, and metalwork like the Ardagh Chalice, and in the case of manuscript decoration had a profound influence on Western medieval art. The manuscripts were produced by and for monasteries, and evidence suggests that metalwork was produced in both monastic and royal workshops. Culdees The Culdees (, "Spouses of God") were members of ascetic Christian monastic and eremitical communities