The early U-boat operations from the French bases were spectacularly successful. This was the heyday of the great U-boat aces like Günther Prien of "U-47", Otto Kretschmer (), Joachim Schepke (), Engelbert Endrass (), Victor Oehrn () and Heinrich Bleichrodt (). U-boat crews became heroes in Germany. From June until October 1940, over 270 Allied ships were sunk: this period was referred to by U-boat crews as "the Happy Time" (""Die Glückliche Zeit""). Churchill would later write: "...the only thing that ever frightened me during the war was the U-boat peril".