This is an Anglicized form of the Old Gaelic patronymic "MacDonnchadha", which translates as "the son of Donnchadha". The name itself consists of elements meaning "brown (donn)", plus "battle (chatha)". Originally, two separate clans existed in Ireland, the first in Connacht, and these MacDonnchadha's were a branch of the MacDermots, the 8th Century Kings of Connacht. The second clan, whose chiefs held the Castle of Kanturk in County Cork, and who were known as the bards of Duhallow, were a branch of the MacCarthys. The name is now rare in Cork, original nameholders, it is believed, changing their name to MacCarthy. There are a number of surname spelling forms, MacDonagh being the popular form, others being MacDonogh and MacDonough; the latter being more popular in County Sligo. Thomas MacDonough (1783 - 1825) was a famous early American naval officer, whilst among the first famine immigrants was Andrew McDonough, aged 30 yrs., a passenger on the Coffin Ship "Jane", of Liverpool, bound for New York in May 1846. The first recorded spelling of the family name is shown to be that of MacDonnagh of Sligo, which was dated 1659, in Petty's, "Census of Ireland", during the reign of Richard Cromwell, known as "The Lord Protector", 1658 - 1660. 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.