In the 15th century these lands were drained by Dutch settlers for agricultural use with the construction of the original sea wall. The population of Wallasea was at its highest in the mid to late 19th century. In 1875 there were 135 inhabitants and there were 13 houses. A school was opened in 1879 and lasted for 20 years. Import of cheap American wheat resulted in an agricultural depression starting in 1875. Most of the island's population left and Wallasea reverted to pasture.