In parts of the _Senchus Mór_,[152] one of the ancient books of law, it is prescribed as a duty of society to pay tithes, as well as to bestow alms and first fruits to the Church, but tithes were not generally nor regularly paid until after the Norman invasion in 1172 A.D.[153] Another subsidiary, but occasionally substantial, means of support was the dues paid by the tribe to the abbot for the performance of various religious functions.[154] The Brehon Laws lay down specifically the reciprocal obligations of the clergy and laity in this manner.[155] In this connection[156] it should be pointed out that owing to its position in the native social system “the Church in Ireland never became as in other lands by turns the servant, the ally, or the master of the State. It was the companion of the people, and an important element in the national life.”
Gifts, or voluntary offerings, were a further source of income, but a fluctuating one, depending largely on the location of the monastery, its reputation, the social condition of its patrons, and a variety of other accidental circumstances. Almost all persons who visited a monastery left something of value, if their means permitted. In early times the offerings, like other payments, were in ounces of gold or silver, or in kind. When Brian Boru visited Armagh in 1004 A.D. he laid on the great altar an offering of twenty ounces of gold, equivalent to $5000 or $7000 at the present day.[157]
The monastery including the whole group of monastic buildings was generally, but not always, surrounded by a strong rampart, commonly circular or elliptical, after the manner of the homesteads of the laity. The enclosure with its bounding rampart was designated in Irish by various names. When the wall was of earth it was called a _rath_, or _lios_. If surrounded by a stone wall it was known as a _caiseal_ or sometimes a _cathair_.[158] Sometimes the monks located themselves in a rath or lios surrendered by a friendly chief,[159] and sometimes the monks built the enclosure themselves.[160] So much was the rampart a feature of the Irish monastery that we find it in connection with the monasteries founded by Irish monks in foreign lands. A _vallum monasterii_ is mentioned by Adamnan,[161] and Columbanus utilised the walls of the old Roman _castrum_ to serve as the _vallum_ for his monastery at Luxeuil.[162] The monastery proper was the space enclosed by the vallum and included the church or churches, the oratories, the refectory, the kitchen, the school, the armarium—a chamber for the preservation of books and literary apparatus, sometimes a special scriptorium, the hospice or guest house, the cells for the monks, and the officinae or workshops for the smith and the carpenter.[163] Outside of the vallum were the various other indispensable buildings connected with the monastery of which the storehouse and the mill are the most important. There was usually a byre for the cows situated in convenient pasture land. If the monastery was located inland there was a fish pond; or a convenient harbour, if near the sea. The various buildings occupied different situations according to local convenience.[164]