Captain Henry McCullough, Lieutenant John McCullough and
Ensign William McCullough all served together as the principals
officers in a company of Colonel Skeffington's Londonderry
Regiment formed in January 1689 for service during The Siege of
Londonderry. It can be reasonably assumed that they were
related, perhaps a father and his two sons, or three brothers or
cousins. Their Regiment was also known as "The Antrim
Volunteers" which probably reflects the origin of the majority of
its members. It was one of six volunteer regiments raised to
defend the city against Catholic supporters of James II.
A British historian has recorded that "the sufferings of the garrison during the Siege of Londonderry are almost unparalleled in history." We are told that a quarter of a dog sold for five shillings, a dog's head for two shillings, horseflesh two shillings a pound, a cat for four shillings, a rat one shilling, a mouse sixpence, salted hides one shilling, and tallow grease four shillings per pound, the latter being the principal diet (mixed with flour) for the closing weeks of the siege. The historian concludes that "the British soldier could not fight without his bed, his beef and his beer; but these hardy Derry volunteers fought on the ramparts by day, and often made sorties by night, and all this on nearly empty stomachs!"
Out of a garrison of 7000 men, 4000 soldiers died during the siege not to mention the innumerable women and children. During the Siege, Skeffington's Regiment unofficially became Major John Mitchelburne's Londonderry Regiment. This able officer, who lost his wife and all his children during the siege, took over command on 19 April 1689 and by June was the acting Governor of the City. Whether the three McCulloughs survived the horrors of the siege is unknown, but their Regiment certainly did, though diminished in size and having to be amalgamated with Crofton's Regt to form a new one on the lifting of the siege.
This new Regiment was taken onto William III's Irish Army establishment as Colonel Mitchelburne's Londonderry Regt on 4 August 1689. "The Antrim Volunteers" went on to fight at The Battle of the Boyne, 1 July 1690, where William III decisively defeated James II's 30,000 man Franco-Irish army. It also fought at The Siege of Sligo in 1691. The Regt was disbanded seven years later in 1698.