The Heydon family name comes from the town of Heydon, in Norfolk, England, the locality of their original estate. Thomas de Heydon (ca. 1185-ca. 1250) of Heydon was a justice in Norfolk County. His son, William Heydon (ca. 1220-1272) succeeded him in the estate and was the father of John De Haydon, the judge, and ancestor of the Devon line. The author assumes that John, William, and James Heydon, three brothers, the immigrated ancestors of the American lines, who appeared in Boston, Dorchester, and Charlestown, Massachusetts, in 1630, were sons of Gidoen Haydon, of Cadhay, of the Devon line. Some of their descendants spell their name "Hayden."