Mercer was born in Aberdeen in the year 1725. His father was a clergyman; his mother, a daughter of Sir Robert Munro, who, after distinguishing himself at Fontenoy and elsewhere, was killed at the battle of Falkirk, while opposing the young “Pretender.” Hugh Mercer did not follow in the footsteps of his father, but linked his fortunes with Charles Edward’s army, as assistant surgeon, fought with him at Culloden and shared the gloom of his defeat—a defeat which was not less bitter because his ears were ringing with the victorious shouts of the army of the Duke of Cumberland.
To change a scene that brought sad memories, Dr. Hugh Mercer, in the fall of 1746, embarked for America. There, on the frontiers of civilization, in Western Pennsylvania, he spent arduous, unselfish years. He was welcomed and loved in this unsettled region of scattered homes.
A rough school it was in which the doctor learned the lessons of life.
In the year 1755, Mercer made his appearance in the ill-fated army of Braddock, which met humiliating disaster at Fort Duquesne. Washington’s splendid career began here and here Mercer was wounded. Of this memorable day of July 9, 1755, it has been said that “The Continentals gave the only glory to that humiliating disaster.”
In 1756, while an officer in a military association, which was founded to resist the aggression of the French and Indians, he was wounded and forced to undergo terrible privations. While pursued by savage foes he sought refuge in the trunk of a tree, around which the Indians gathered and discussed the prospect of scalping him in the near future. When they left he escaped in the opposite direction and completely outwitted them. Then began a lonely march through an unbroken forest, where he was compelled to live on roots and herbs, and where the carcass of a rattlesnake proved his most nourishing meal. He finally succeeded in rejoining his command at Fort Cumberland. In recognition of his sacrifices and services in these Indian wars, the Corporation of Philadelphia presented him with a note of thanks and a splendid memorial medal. In the year 1758 he met George Washington and then it was that Pennsylvania lost a citizen. In Fredericksburg, at the time that Mercer came, lived John Paul Jones, and we do not doubt that they often met and talked of their beloved Scotland.
During his first years in Fredericksburg, Mercer occupied a small two-story house on the southwest corner of Princess Anne and Amelia Streets. There he had his office and apothecary shop. The building is still standing.
An Englishman, writing at this time of a visit to Fredericksburg, calls Mercer “a man of great eminence and possessed of almost every virtue and accomplishment,” truly a sweeping appreciation.
Mercer Joins Masonic Lodge
He belonged to Lodge No. 4, of which George Washington was also a member, and he occasionally paid a visit to Mount Vernon.
In September, 1774, the Continental Congress met in Philadelphia. The war cloud was lowering, it broke, and when the Revolution swept the country, Mercer was elected Colonel of the Third Virginia Regiment.