The coastline of East Kent has changed dramatically over the last two thousand years since the Roman Invasion. This explains the location of the early fortifications of Reculver and Richborough which were positioned to guard the north and south entrances to the Wantsum Channel. The Isle of Thanet, an island at that time was not defended. Over time the channel silted up, but it was still possible to sail to Canterbury in the 15th century. All that is now left is the River Stour.