Simson Werke-Suhl was the original company taken over by the Nazis due to its Jewish ownership and re-named Gustloff Werke, prior to & during the war. I don't know about the connection to Merkel Bros. founded in 1898 also in Suhl, but assume there is a direct link, the German Gun Collectors site can probably answer that much better.

Suhl in a town in Germany and Thuringen is an area or state in Germany.

Your gun woluld be a Simpson BLE.

Not much iformation, but hope its helps you out some.