Complex sentence: It served this function up to the so-called "Reichspogromnacht" of 9-10 November 1938, when it was severely damaged on the inside by plundering, though the exterior remained nearly intact.
Split into simpler sentences: It served this function up to the so-called "Reichspogromnacht" of 9-10 November 1938. At this night it was strongly damaged in the inside by plundering, though the exterior remained nearly intact.