In hoc signo vinces:

A Latin rendering from the greek "en toutoi nika" - "by this, be victorious!" Though the Latin is less ambiguous, "In this sign you will conquer!"
James Bowen, my great, great, great, great grandfather adopted the above crest and motto for the coat of arms for the Bowens, some time between his birth in 1740 at Salisbury, Wiltshire, and his mysterious death on November 10th 1796 at Martinique in the Carribean. A King's man or a privateer? I'll endeavour to find out.