AIDS, a term of mediaeval finance, were part of the service due to a lord from his men, and appear to have been based upon the principle that they ought to assist him in special emergency or need. The occasions for demanding them and the amount to be demanded would thus be matters of dispute, while the loose use of the term to denote many different payments increases the difficulty of the subject.
Both in Normandy and in England in the 12th century the two recognized occasions on which, by custom, the lord could demand "aid" were (1) the knighting of his eldest son, (2) the marriage of his eldest daughter; but while in England the third occasion was, according to Glanvill, as in Normandy, his payment of "relief" on his succession, it was, according to the Great Charter (1215) , the lord's ransom from captivity. By its pro visions, the king covenanted to exact an "aid" from his barons on these three occasions alone—and then only a "reasonable" one —except by "the common counsel" of his realm. Enormous im portance has been attached to this provision, as establishing the principle of taxation by consent, but its scope was limited to the barons and the City of London, and the word "aids" was omitted from subsequent issues of the charter. The barons, on their part, covenanted to claim from their feudal tenants only the above three customary aids. The last levy by the Crown was that of James I. on the knighting of his eldest son (1609) and the mar riage of his daughter (1613) .
From at least the days of Henry I. the term "aid" was also applied (1) to the special contributions of boroughs to the king's revenue, (2) to a payment in lieu of the military service due from the Crown's knights. Both these occur on the pipe roll of 1130, the military payment as auxilium militum (and possibly as ium comitatus). The borough "aids" were alternatively known as "gifts" (dons), resembling in this the "benevolences" of later days. When first met with, under Henry I., they are fixed round sums, but under Henry II., as the Dialogue on the Exchequer explains, they were either assessed on a population basis by Crown officers or were sums offered by the towns and accepted by them as sufficient. In this case the townsfolk were collectively responsible for the amount.
The same loose use enabled the early barons to demand "aid" from their tenants on various grounds, such as their indebtedness to the Jews, as is well seen in the Norfolk fragments of returns to the Inquest of Sheriffs (Ii7o).
Sheriff's aid was a local payment of a fixed nature paid in early days to the sheriff for his service. It was the subject of w hot dispute between Henry II. and Becket in '163.