Ernst Bogislaw von Croÿ (26 August 1620, Finstingen (Fénétrange) – 6 February 1684, Königsberg) was a Lutheran Administrator of the Prince-Bishopric of Cammin and official in the service of Brandenburg-Prussia.
Juncker was born Fénétrange, Lorraine, and while a young student at the Pont-à-Mousson seminary he decided to devote his life to the American missions, attaching himself to the Diocese of Cincinnati, Ohio.