The only concentration camp to tattoo numbers on prisoners was at Auschwitz and rarely on babies. When babies were tattooed with numbers it was generally on their thigh or bottom as their arms were too small.
200-year-old Henry 'Hank' Morgan shares his name with the main character of Mark Twain's "A Connecticut Yankee in King Arthur's Court". Henry Morgan is also the name of the 17th-century privateer as depicted on the "Captain Morgan" rum label.
In the pilot and last episode, Henry and Abe play chess. In Independence Day (1996), Julius and David Levinson (Jeff Goldblum) play chess. Julius and Abe are played by Judd Hirsch, David's father but Henry's son.
Henry plays an immortal man with Adam (Burn Gorman) having the same condition. Burn Gorman played Dr Owen Harper in Torchwood working along side Captain Jack Harkness (John Barrowman) who was an immortal.