It were Agfa and Gevaert that merged.
Wolfen is the name of the place were Agfa's primary filmplant was located. Preceeding that merger the primary Agfa-company (located in East-Germany) and the new erected Agfa-company (located in West-Germany) split their trade and legal connections and the primary company gave itself a new brand name: Original Wolfen
There were companies that got rights to use the Agfacolor principle before WWII. The others were allowed by the surrender of Germany on Allied conditions to use freely Agfa patents. Amongs others this gave the freedom to evade Kodak patents.