This old-established and interesting surname has two possible origins. Firstly, it may be a dialectal variant of Cowhill, a locational name from a hamlet so called near Thornbury in Gloucestershire, which is also the name of a locality in the Chadderston urban district of Lancashire. These placenames are composed of the Olde English elements "cu", cow, and "hyll", hill; hence "the hill where cows grazed". However, in some instances, Cowell may be of Old Gaelic origin, as the Anglicized form of "Mac Cathmhaoil", composed of the Gaelic prefix "Mac", son of, and a personal name from "cathmhaol", battle chief. The MacCathmhaoil sept were located in the Clogher area of County Tyrone, where later they became an important church family. The name is also found here as MacCawell, and is used colloquially for Campell in Tyrone. The first recorded namebearer derives from this source in the 10th Century (see below), while from the former source above, Henry de Cuwell (Northamptonshire, 1196), Thomas de Cuhull (Gloucestershire, 1221), and John Cowell (Lancashire, 1401), derive their surname. John Cowell (1554 - 1611) was Professor of Civil Law at Cambridge (1594 - 1610), and master of Trinity Hall, Cambridge (1598 - 1611). The first recorded spelling of the family name is shown to be that of Cionaidh Ua Cathmhaoil, which was dated 967, in "Ancient Gaelic Record", during the reign of Brian Boru, High King of Ireland, 940 - 1014. 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.