Greetings Jerome! Thomas Archer seems to have gone by various forenames. I believe "Thomas" was his proper given name, but he is often referred to colloquially as "Tam" ( a Scots abbreviation of Thomas/Tom); "Tom" and even "Willie/Wullie". The latter name may have been simply a case of an outlaw using an alias. Alternatively, maybe his given name was "Thomas William Archer" from which all the others mentioned here could have been legitimately derived. In one song Ive heard he was described as "Dark Tam" a man of "medium height, but extremely powerful build, like a bull".