Recorded as Senett, Sennett, Sinnatt, Sinnott, Sinnett, Synnot, and others, this is an English surname, and widespread in Ireland, where it was also gaelicized as Sionoid. The origination is from the pre 7th century Olde English personal name Sigenoth meaning "victory-brave" and recorded as Synondus in the Latinised register of the Abbey of Bury St. Edmunds, Suffolk in 1095. Prominent in County Wexford, Ireland, since the 13th Century (see below), in its various spellings it is the most numerous of Anglo-Norman names which followed the Invasion of Ireland by Strongbow, earl of Pembroke, in 1170. Until the reign of Oliver Cromwell (1649 - 1658) they possessed extensive estates and held important public offices in the country, but after the defeat of King James 11nd at the battle of the Boyne in 1690, many left for other countries. Early recordings include Stephen Sinot in the Hundred Rolls of landowners of the county of Suffolk in 1273, Johannes Sennyett in the Poll Tax rolls of Yorkshire in 1379, and David Synnot, the governor of Wexford, who was killed in its defence during the siege by Cromwell in 1649. The first recorded spelling of the family name is shown to be that of John Synod. This was dated 1247, in the barony of Forth, Ireland, Surnames became necessary when governments introduced personal taxation. In England this was some times known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.