He was the commanding general of all British forces in North America during the Seven Years War. He had a long and varied military career. His military heyday occurred during the late 1750s, with the Portsmouth expedition in which he led a force of 14,000 along with Admiral Boscawen's fleet of 151 vessels. Amherst and his men successfully took Fort Ticonderoga while General James Wolfe captured Quebec and General John Prideaux and Sir William Johnson seized Fort Niagara. In 1763, Amherst's military reputation was tarnished with his difficulties during Pontiac's War and accusations of purposefully spreading small pox among American Indians.