When was Rin Tin Tin born?

If Rin-Tin-Tin was found on the battlefield, as one story goes, it would have been September 15, 1918. See Susan Orlean's Rin-Tin-Tin: The Life and the Legend.

Another very likely story of Rin-Tin-Tin's birth is that he was the son of an adult male German shepherd found on the battlefield that day and then mated to a female German shepherd; if so, he was born around the time of the Armistice. That is the first story that Lee Duncan, Rin-Tin-Tin's owner and trainer, told (in October, 1919, to the Los Angeles Times) and that three officers of his squadron also told. See Rin-Tin-Tin: The Movie Star, available on Amazon.