Recorded in over fifty different spellings including Cohan, Cohen, Cohn, Cohane, Kohen, Kohn, Kun, Kagan, Cagan, Cohansky, and many others, and found in its different spellings throughout Europe, this is a surname which has two quite distinct and separate origins. The first and most popular being a Jewish caste surname. This developed from the original Hewbrew word "kohen", meaning a priest. However not all Jews bearing this name belong to the priestly caste which descended from Aaron, the brother of Moses. In the 18th and 19th centuries many Russian members of the faith changed their name to Kogan or Cagan as examples, to avoid forced military service in the army, priests being the only males exempt from such service. The second possibility is that it is a form of either of two ancient pre 10th century Gaelic surnames originally O' Cadhain of the province of Connacht, or O' Comhdhain from Ulster. The prefix O' indicates male descendant of, plus the personal bynames "Cadhan" mean wild goose, that is to say a soldier of fortune or mercenary or from "Comhdan", meaning a shared gift. Examples of the surname recording taken from surviving early registers of birth, deaths and marriage include that of John Cohn who married Anne Barlow at the church of St Bartholomew the Less in the city of London in 1649, the birth of Levy Issoscher Cohen at the Mambro Synagogue, London, on November 24th 1772, whilst on August 20th 1864, Michael Cohen was born at Claremorris, in County Mayo, Ireland. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.