This interesting surname has two distinct possible sources. Firstly, the surname may be of Irish origin, and is an Anglicized form of the Gaelic "O'Muirgheasa", descendant of "Muirgheasa", a personal name apparently derived from the elements "muir", sea, and "geas", action, and are a branch of the "Ui Fiachra", having their territory at the southern side of Sligo Bay. These are of MacDermot stock, being descended from Muiris, the grandson of a famous MacDermot. However, there is no Gaelic sept of Morrissey associated with Munster or Leinster. There was a very powerful family called de Marisco, whose first representatives in Ireland were Normans, attached to the house of Ormond, through which they obtained extensive grants of land. Many of the Norman families became thoroughly hibernicized, and the de Mariscos adopted the patronymic MacMuiris, and in due course this became, in many cases, Morrissey. On March 2nd 1824, John Morrissey married Margaret Daly at Currow R. C. Church, County Kerry, and James, son of James and Margaret Morrissey, was christened at Killarney, also in County Kerry. One Edward Morrisey, a famine emigrant, aged 25 yrs., arrived in New York on June 15th 1846, aboard the "Hottinguer" from Liverpool. The first recorded spelling of the family name is shown to be that of Niall O'Morrissey, of Sligo, which was dated 1659, in the "All-Ireland Census", during the reign of Richard Cromwell, known as "The Lord Protector", 1649 - 1659. 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.