This surname is of Anglo-Saxon origin, and a locational name, the primary source of which is the parish and village of Eydon near Daventry in Northamptonshire. Recorded as "Egedon" in the Domesday Book of 1086, and as "Eydon", and "Eyndon" in the 1254 "Valuation of Norwich", the initial element of the placename is the Olde English pre 7th Century personal name "Aega", also found in Aynho, Northamptonshire, with the Olde English "dun", down, hill, mountain; hence, "Aega's dun". Locational surnames, such as this, were originally given to local landowners, and the lord of the manor, and especially as a means of identification to those who left their birthplace to settle elsewhere. It is also possible however, that the surname is locational from the parish and hamlet of Aydon near Corbridge in Northumberland, a supposition based on the fact that this hamlet was recorded as "Eyden" in the 1285 Close Rolls of that county. Finally, the source may be topographical from residence by any of the rivers called Eden, such as the River Eden in Cumberland and Westmorland, and also in Sussex and Kent. These rivers appear to be named with an ancient British word meaning "to gush forth". In 1553, Thomas Eydon and Annes Lumberd were married at Cropredy, Oxfordshire, and in 1584, Fayth Eyden and John Harryson were married at Faversham, Kent. The first recorded spelling of the family name is shown to be that of Nicholas de Edune, which was dated 1178, in the "Pipe Rolls of Northumberland", during the reign of King Henry 11, known as "the Builder of Churches", 1154 - 1189. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.