This is a surname of medieval Scottish origin. It is a form of MacThaidhg, meaning the son of Tadhg, an ancient male given name meaning the bard or poet. Tadhg was the name borne by the brother of Connor O'Connor, King of the Irish province of Connaught who died in 973 a.d, and it also appears as Tathkr and Tand in ancient Norse records relating to their kingdom in Ireland. Over the centuries MacThaidhg has acquired a number of spellings including: MacCaig, MacCague, MacKaig, MacKeeg, MacKeig, McKeag, MacKegg, MacKeague and Caig, the last mentioned form being widespread in Galloway and Ulster. Amongst the early recordings are those of Andrew McCaig in the Scottish Acts of Parliament dated 1567, and Jennat Mackcaige in the Register of the Privy Council of Scotland in 1685. In the same year Archibald McKeag, a rebel in the Kilcheran parish, Kintyre, was entered in records known as "The Commons of Argyll". The surname Caig is particularly well recorded in parish registers of Kircubbin, County Down, where on January 13th 1792, Ann, daughter of Henry Caig, was christened. Recordings of the name from Scotland include: John and Andrew Caig of the parish of Buittle, Kircudbrightshire (1684); and John Caig, who married Margaret Stewart in Tinwald, Dumfries, on May 29th 1857. The first recorded spelling of the family name is shown to be that of John Makkaig, of Wigtownshire, which was dated 1486, in the "Exchequer Rolls of Scotland", during the reign of King James 111 of Scotland, 1460 - 1488. 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.