Although it might have been written earlier it is thought that James Francis Wade who was a copier of manuscripts wrote the verses and the music of this famous hymn while living at the Roman catholic College for Englishmen at Douai in France in about 1745.
They were included in a packet of manuscripts sent to the English Roman Catholic College in Lisbon in 1750 and found their way to England in 1785.
In 1841 Frederick Oakeley was the minister at the Margaret Chapel in London's West End and gave this version, which he had translated from the Latin, to his congregation. It was known originally as 'Adeste, fideles' (Come Faithful Ones). In both versions it had eight verses and usually the eighth is only sung on Christmas Day.
(Information from 'Famous Hymns and Their Stories' by Christopher Idle and 'Best Loved Christmas Carols' compiled by Martin Manser)
This version is from the Northern Baptist Association - The Big Sing in Newcastle-upon-Tyne in 2008.
Probably one of the best know Christmas Carols, sung everywhere every year.