Prachum Phongsawadan vol 20 (1963), p 6, Vajiravudh

A royal proclamation dated 2 august 2456 be (1913 ce), by which king rama vi (vajiravudh) of siam granted the family name "นิลกุล" (nilakul; rtgs: ninlakun) to an official and a son. Date: 1963.