from Irish Heritage Research.

An outline of the O’Dubhda Family History

The Uí Faichrach — early origins
There are many people of Irish descent who can justly claim an ancestry as ancient and royal as that of any of the famous European dynasties. Among them are the O’Dubhda family (pronounced "O’Dooda"), including the O’Dowda, O’Dowd and other variant spellings, who are descended (with many other families) from a people in the West of Ireland once known as the Uí Faichrach ("Ee Fee-a-crock"). This name derived from a 5th century pagan king of Connacht called Fiachra ("Fee-a-cra"). His grandson Daithi ("Daw-hee") also became king and was killed by lightning about 445 A.D. His grandson Aillil ("Al-ill") succeeded as King of Connacht and later King of Tara until 482.

The O’Dubhda surname
The Uí Faichrach provided successive kings of Connacht for a long period, but their sphere of influence became confined to North Connacht. In the late 10th century, their king was named Aedh Ua Dubhda i.e. Hugh, the grandson of Dubhda ("Dooda"). He was king of an area roughly corresponding to the two counties of Mayo and Sligo. He is recorded as having ‘died an untroubled death’ in the year 982, making this surname one of the oldest in Europe. As the use of surnames became more widespread, descendants continued to use the name O’Dubhda to distinguish their own royal family. This is pronounced "O’Dooda", but there are as many as forty different variations on the surname.

The O’Dubhda Taoiseach
The O’Dubhda remained kings of North Connacht until the 13th century. However, great changes took place in Irish society and they lost control over much of their former lands before being confined to the barony of Tireragh ("Tea-rare-ra") meaning ‘the country of Fiachra’ in Co. Sligo. As a result, they gradually dropped the use of the title king. This was replaced in time by the title Taoiseach ("Tea-shock"), i.e. chieftain or leader. This term is now used as the title of the Irish Prime Minister. The man who became Taoiseach was generally referred to by his surname only, e.g. O’Dubhda. In this way he came to be referred to as chief of his name. He was elected according to the old Irish laws and sometimes there was dispute over the leadership. One means of avoiding conflict was by the selection of a Taoiseach-elect, called a Tanaiste ("Thaw-nishta"). This term is now used for the Irish Deputy Prime Minister. The election and inauguration was presided over by the ollamh ("Ulav") or professor of the Mac Firbis family of scholars.

The O’Dubhda is unique in having a detailed account of the inauguration ceremony of their Taoiseach preserved in an ancient manuscript of the Mac Firbis scholars. This manuscript, known as the Great Book of Lecan, was written near Enniscrone in Tireragh between 1397 and 1418 and is now carefully preserved as one of our Irisn national treasures in Dublin. One of the most generous sponsors of the Mac Firbis scholars was Tadhg Riabhach O’Dunhda (’Dark Teige’), who became Taoiseach of Tireragh in 1417. He is particularly remembered in this manuscript where his death is recorded at Enniscrone Castle. This unique treasure preserves much of our ancient Irish heritage. It contains information relating to the history of hundreds of different Irish families. Both the Mac Firbis bardic scholars, who wrote it, and the O’Dubhda rulers who supported them, deserve our rememberance.

O’Dowda and O’Dowd, Dowd and Doody, etc.
The ancient laws of Ireland, known as the Brehon Laws, continued in use until the early 1600s. The last Taoiseach to be elected under these was Tadhg Buí O’Dubhda (’Blonde Teige’). He was inaugurated in 1595, and led his army south to the battle of Kinsale in 1601. He never came back. Tradition states that he survived the battle and settled in Co. Kerry, where his family later became known as Doody. During the 17th century, the rest of the O’Dubhda ruling family was displaced from their homeland, where they had owned 24 castles and 52 towns, including Enniscrone. They split into two main branches, and these settled in Co. Mayo. In dealings with government officials using the English language several different spellings of the surname were introduced, one branch using the spelling of O’Dowda, while the other branch became known as O’Dowd. Two centuries earlier a third branch had left and settled near Dublin, where they became known as Dowd. Although there are more than 40 other variations, Dowd and O’Dowd are now the most common versions of the surname. There are many descendants now loving who can trace their ancestry directly back to the original O’Dubhda kings.