Complex sentence: For more than 200 years, both territories were ruled in personal union by the Stolberg (from 1548: Stolberg-Stolberg) line, until in 1645 the dynasty again divided the dominion and split off the Stolberg-Wernigerode branch.
Split into simpler sentences: For more than 200 years, both territories were ruled in personal union by the House of Stolberg. Held by the Stolberg-Stolberg line from 1548, the comital dynasty again divided their dominions and split off the Stolberg-Wernigerode branch.