 He served under George Washington during the Revolutionary War as Superintendent of the Eastern Indians and Colonel of Infantry, and he recruited Indian tribes of Eastern Maine to stand with the Americans during the war and participated in border negotiations between Maine, and New Brunswick.Allan was born in Edinburgh Castle in Scotland, the son of Major William Allan (military officer) (1720 –1790), 'a Scottish gentleman of means and an officer in the British Army', and his wife Isabella, daughter of Sir Eustace Maxwell.The Allan family temporarily resided in Edinburgh Castle where they had sought refuge during the Jacobite rising of 1745, under the Deputy Governor, General George Preston, Commander-in-Chief of Scotland.