Kent coastline of Kent is continuously changing, due to tectonic uplift and coastal erosion. Until about 960, the Isle of Thanet was an island, separated by the Wantsum channel, formed around a deposit of chalk; over time, the channels silted up with alluvium. Similarly Romney Marsh and Dungeness have been formed by accumulation of alluvium. Kent's principal river, the River Medway, rises near East Grinstead in Sussex and flows eastwards to Maidstone. Here it turns north and breaks through the North Downs at Rochester, then joins the estuary of the River Thames as its final tributary near Sheerness. The Medway is
Maidstone the river to allow clothes to be rinsed in the cleaner water away from the banks. Neolithic finds have revealed the earliest occupation of the area, and the Romans have left their mark in the road through the town and evidence of villas. The Normans set up a shire moot, and religious organisations established an abbey at Boxley, hospitals and a college for priests. Today’s suburb of Penenden Heath was a place of execution in medieval times. Maidstone played a key role during the Peasants' Revolt of 1381. The rebel priest John Ball had been imprisoned there and was freed