Rayleigh owes its origins to the flints on Hambro Hill, which attracted its first human residents as long ago as the Stone Age. In Saxon times, the focus moved to the area covered by the modern High Street, but it was not until Rayleigh Castle was built under the Normans that the town really came to life. Its market and fair made it one of the principal towns in southeast Essex throughout the medieval period, and many significant historic buildings from the 14th century onwards, including Holy Trinity Church, the Dutch Cottage and the windmill, survive. The town's importance grew with the coming of the railway in 1889.