Recorded in many forms including Dineen, Dinneen, Dinnen, and sometimes Denning, this is an Irish surname. It is a developed spelling of the ancient Gaelic surname O'Duinnin, from the personal name "Donn" meaning brown. As Denning, Diana and Diane, it was also found on the list of synonyms equated with Dineen compiled by the Cunard company in relation to emigrants to the United States of America in the 19th century. The great majority of nameholders and then mainly as Dineen, are found in County Cork, and especially in the south western part of the county anciently known as Corca Laoidhe. The family were famous as poets and historians, providing a succession of hereditary poets and historians to the Clan MacCarthy and occasionally to the O'Sullivans, who disputed ownership of the region for many centuries. Early examples of the surname recordings include those of Tadhg O'Dineen, poet to the earl of Clancarty, and a prominent member of the 17th century school of Irish poetry in Blarney, County Cork, whilst at Donagh, in County Donegal, Letitia Denning married Robert Hilliard on August 28th 1846. Peter Dinnen was an Irishman who fled the Great Famine of 1846 - 1848. He boarded the ship "Defense of Liverpool" on April 17th 1847, and it is known that he reached the port of New York on about May 10th of that year. 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.