When Jens Martinus Terkelsen was born on 9 November 1843, in Hjelmsted, Serritslev, Hjørring, Denmark, his father, Terkel Larsen, was 45 and his mother, Ane Maria Thomasdatter, was 34. He lived in Serritslev, Børglum, Hjørring, Denmark in 1845. He died on 16 January 1846, in Hjelmsted, Serritslev, Børglum, Hjørring, Denmark, at the age of 2, and was buried in Hjelmsted, Serritslev, Børglum, Hjørring, Denmark.