Tilbury Fort is an artillery fort on the north bank of the River Thames in England, built by King Henry VIII to secure it against France. It was later reinforced over concerns of invasion by the Spanish Armada in 1588.

A Spanish fleet of about 130 ships. It sailed in late May 1588, under the command of the Duke of Medina, with the mission of escorting an army from Flanders to invade England. The aim was to overthrow Queen Elizabeth I and Protestantism in England.