Complex sentence: Once it was a defensive stronghold for today's regional centre and its twin city, Bad Radkersburg on the other side of the river Mura in Austria, the towns split apart in 1919 when the state of Styria was divided between Austria and Slovenia.
Split into simpler sentences: Once it was a defensive stronghold for today's regional centre and its twin city, Bad Radkersburg on the other side of the river Mura in Austria. The towns split apart in 1919 when the state of Styria was divided between Austria and Slovenia.