Complex sentence: The southern boundary of Pennsylvania, and thus of Lancaster County, was in dispute for years, culminating in nine years of armed clashes during the Maryland-Pennsylvania boundary dispute beginning with the 1730 establishment of Wright's Ferry across the Susquehanna River.
Split into simpler sentences: The southern boundary of Pennsylvania, and thus of Lancaster County, was in dispute for years with Maryland. Nine years of armed clashes accompanied the Maryland-Pennsylvania boundary dispute, beginning with the 1730 establishment of Wright's Ferry across the Susquehanna River.