On 28 March 1971 Rugbyclub DIOK was founded with the backing of the Leidsch Studenten Rugby Gezelschap. DIOK history page
A later club page describes the start as a small group of rugby enthusiasts. DIOK 55-year page
The badge carries a lion. The club’s charity arm cites the shared lion emblem, and shared colours, as one reason a Lions club was founded out of the rugby club. No fetched source explains why DIOK chose a lion in the first place. DIOK Lions page