Recorded in several spelling forms including O'Dowd, Dowd, Dood, Doody, Dowda and Duddy, this ancient name is Irish. It derives from the pre 10th century Gaelic O' Dubhda. The prefix "O" indicates "male descendant of", plus the personal name Dubhda. This is from the word "dubh" meaning black, and probably referred to a chief with particularly dark hair or complexion. The sept claim descent from Fiacha, the brother of Niall of the Nine Hostages, a 4th century king of Ireland. For many centuries the O' Dowds were the leading sept in the ancient territory of Ui Fiachrach. This comprises the modern counties of Mayo, Sligo and parts of South Galway. Several clan members were bishops of the see of Killala, County Mayo. In the 17th Century the O' Dowds fought in the army of King James 11nd of England, and their chief at that time, was killed at the battle of the Boyne in1690. He was reputed to have been seven feet tall. Examples of the surname taken from surviving charters and registers include: Michael Dowd, who embarked from Sligo on May 25th 1847 to escape the dreadful Potato Famine, raging at that time. He was known to have reached New York, although his later life is not proven. The first recorded spelling of the family name is shown to be that of Bhrian O'Dowd, chief of Ui Fiachrach in 1354. It is said that he drove the Anglo-Norman settlers from his territory. Surnames became necessary when governments introduced personal taxation, and throughout the centuries, surnames in every country have continued to "develop," sometimes leading to astonishing variants of the original spelling.