Recorded in the spellings of MacCrossan, McCrossan, Crossan, Crosby and Crosbie, this is a famous Irish surname, which is particularly prominent in Australia. It originates from the pre 10th century Ancient Gaelic Mac An Crosain, whose meaning was the son of the young Cross. This may be a reference to a location, but is more likely to have described a specific Christian, a secular person who devoted himself to following the faith. Most Irish and Gaelic surnames originate from a nickname for the first chief of the clan, and this surname is probably no different. It is said that the clan originated in County Tyrone, although there has been an associated branch in Counties Leix and Offally since the 12th century. The first recorded nameholders were probably Henry an Crossan and later Richard MacCrossan, both it is said, were Bishops of Raphoe in the Middle Ages. Members of the clan were at various times bards to the O'Mores and the O'Connors, both claimants to various early kingships. In the Chancery Rolls of the year 1550, one Owen MacCrossan is recorded as a "rymer" who received a pardon. This pardon may have related to the fact that some of the MacCrossan's supported the government, or as it is sometimes put by researchers "espoused the English cause", and changed their name to Crosby and Crosbie. They held lands estimated at over 20,000 acres mainly at Ardfert, in County Kerry, from the 16th century or possibly earlier, being described as "powerful landlords". If indeed they did ever take the side of the government, this did not last. Pierce Crosbie who turned Catholic in about 1640, lead some of the Irish cavalry against Cromwell in 1651, and others later fought William of Orange in 1690.