and to have formed part of the original curtain walls, though its function remains unclear. The priory's church was notably long, measuring some in length and in width. The cloister, situated on the south side of the church was square. Dovecot The priory complex incorporated a large dovecot (also known as a columbarium), which has been almost perfectly preserved. Located to the south east of the chancel, Frank Keohane describes it as "arguably the finest medieval dovecot surviving in Ireland." The inner walls of the dovecot are built in square compartments in regular tiers to a height of fifteen feet. There are three hundred and fifty two niches, divided into eleven tiers each containing thirty-two compartments. The tiers begin above ground level so as to allow for the collection of droppings and end well below the flight hole in the roof since doves will not perch near busily frequented exits. The columbarium at Ballybeg, is typically located away from the main priory buildings, and still conserves a string course around the circumference of the building which served not only as a structural strengthening of the building but also to prevent weasels, martens or other vermin from scaling the walls to the entrances. The columbarium's importance stemmed from its having been a source of revenue for the priory as its principal agricultural purpose was the production of fertiliser. Pigeon fertiliser (guano) was essential for herb gardens and economically more highly valued than equivalents produced by cattle, sheep or pigs. It was also a sine qua non for the successful growing of hemp which was widely used for cloth, rope and sack making. Since pigeons could themselves be regarded as vermin and capable of wreaking damage on grain crops, columbaria were strictly controlled by medieval law. While tenants and others were permitted to keep a few pairs of doves in their roof-attics, a dovecot, such as that at Ballybeg, was the exclusive prerogative of the landowner who, in turn, was restricted to one nest per arpent, a medieval French measure of land equal to roughly an acre and a quarter. From this, we can infer that at the time of the construction of the truc at Ballybeg, the priory owned something in the region of four hundred and of land or four carucates. At the time of its dissolution, Ballybeg seems to have been in possession of less than two carucates of