Complex sentence: The island traded hands dozens of times in the ensuing years until finally, in the 1860s it was acquired by James Lick, whose estate maintained control of the island for approximately the next 25 years.
Split into simpler sentences: The island traded hands dozens of times in the ensuing years. It was finally acquired, in the 1860s by James Lick, whose estate maintained control of the island for approximately the next 25 years.