Clinton, along with Major Generals William Howe and John Burgoyne, was sent with reinforcements to strengthen the position of General Thomas Gage in Boston. They arrived on 25 May, having learned en route that the American War of Independence had broken out, and that Boston was under siege. Gage, along with Clinton and Generals Howe and Burgoyne discussed plans to break the siege. Clinton was an advocate for fortifying currently unoccupied high ground surrounding Boston, and plans were laid to occupy those spots on 18 June. However, the colonists learned of the plan and fortified the heights of the Charlestown peninsula on the night of 16–17 June, forcing the British leadership to rethink their strategy.