Sir, J P Duggan (July 26th) implies that the commemoration of a small battle would be an acceptable cause for a celebration or parade. He claims that the 12th is the anniversary of "unhappy" Aughrim rather than the "bloody" Boyne.
Aughrim was a far larger battle than the Boyne, as big as any battle in Europe at the time. St Ruth's army has been estimated at 16,000 foot, 3,000 horse and 2,000 dragoons against Ginkel's army of 20,000 men. In contrast to the Boyne, where an orderly retreat by the Jacobites saw relatively few killed, Aughrim became wholesale slaughter when the Jacobite cavalry abandoned their infantry to the Williamite advance. In Aughrim, 7,000 Jacobites and 2,000 Williamites were killed in one day's fighting. Unhappy indeed.
With regard to the dates of the battles, by the late 17th century the Julian Calendar was 11 days adrift of the Gregorian. The Battle of the Boyne took place on July 1st, Aughrim on July 12th the following year. The convention is to commemorate dates by converting to the Gregorian Calendar, hence the anniversary of the Boyne is the 12th and that of Aughrim the 23rd. Yours, etc., Rathmines, Dublin.