Complex sentence: Following the Munich Agreement in 1938, the border regions of Bohemia historically inhabited predominantly by ethnic Germans (the Sudetenland) were annexed to Nazi Germany; this was the only time in Bohemian history that its territory was politically divided.
Split into simpler sentences: Following the Munich Agreement in 1938, the border regions of Bohemia historically inhabited predominantly by ethnic Germans (the Sudetenland) were annexed to Nazi Germany. This was the only time in Bohemian history that its territory was politically divided.