Niels is a male given name, equivalent to Nicholas, which is common in Denmark, Belgium, Norway (formerly) and the Netherlands. The Norwegian and Swedish variant is Nils. The name is a developed short form of Nicholas or Greek Nicolaos, after Saint Nicholas. Its pet form is Nisse, and female variants are Nielsine, Nielsina, and Nielsa. Notable people with the name include: Niels, King of Denmark (1065–1134) Niels, Count of Halland (died 1218) Niels Aagaard (1612–1657), Danish poet. Niels Aall (1769–1854), Norwegian businessman and politician.
https://en.wikipedia.org/wiki/Niels