Question: What is shared by the official U.S. state song "The Song of Iowa" and the German Christmas song "O Tannenbaum"?
Sentence (from "The Song of Iowa"): "The Song of Iowa" is the official state song of the U.S. state of Iowa, written by S. H. M. Byers in 1897 and adopted by Iowa State Legislature in 1911.
Relevant evidence: Yes