He was baptised as 'Thomas Brown' in the Roman Catholic rite at Araluen, a gold mining town near Braidwood, on 25 February 1855.
This took place three-and-a-half years before his marriage in the Roman Catholic Church at Braidwood, St Bede's, to Hannah (Annie) Nicholson.
Thomas's baptismal record says he was a labourer living at Braidwood at the time of his baptism, and that his father was Patrick Brown and his mother 'a native Black'.
His birthdate was given as 'about the year 1839'.
Other records suggest it was actually 1837.
The settlement of Bourke began in 1835 when the colonial surveyor, Thomas Mitchell, built a small stockade there called 'Fort Bourke' during his visit to the area.
The only way Thomas's father, Patrick Brown, a convict, could have been there was if he had been assigned to Mitchell's party, or to one of the earliest settlers in the area.
The word 'Bourke' may have been confused with the name of Patrick Brown's new partner, Catherine Rourke.