The earlist relative I have been able to trace was Joseph Thom born 1743, arrived in US 1773 with an unknown brother. Married Elizabeth Craig and had ten children. Word of mouth states that Thom family left England with Pilgrims and went to Holland. They may have spread from there to other locations on the continent.
Thom in gaelic means twin. The verbal history says that Thoms were Irish, moved to Scotland, thence England, Holland, back to England then to New World. My line is Protestant.
Arthur J Thom