The Arroasian order was one of the most important of the twelfth-century congregations of canons regular of St Augustine. The development of the institute of the canons regular may be said to have had two phases. From early christian times it was comparatively common for communities of priests, forming the staff of cathedral or large city churches, to imitate the monastic rule of life. In the general disorder which followed upon the barbarian invasions this practice disappeared. It was revived again under Charlemagne, only to suffer a similar fate on the break-up of his empire. At this stage we find secular priests performing collegiate and parochial work while living a regular life under a rule usually given them by a bishop.

Statements as to the number of (and the elements composing) the government force which faced the French at Castlebar on Monday morning, 27 August 1798, differ widely and some of them are surprising. A history of the Irish rebellion published in 1898 by F. W. Palliser puts the number of the government troops at 16,000 or 17,000. Dr Richard Hayes gives the number as 5,000 infantry and 1,500 cavalry. Fortescue speaks of Lake arriving at Castlebar ‘ where Hutchinson had already assembled four thousand men chiefly militia and fencibles ‘, but he also speaks of his having been next morning at the time of the attack ‘ in a strong position with some 1,700 men ‘. The aggregate strength is by many writers stated as relatively ‘ more than thrice ‘ that of the French; a contemporary example of this is in the Annual Register for 1798.