Complex sentence: It was further strengthened by the Marathas under the leadership of Shivaji in 1677 AD, who recaptured it from the Bijapur sultans who had originally taken control of the fort from the Marathas.
Split into simpler sentences: It was further strengthened by the Marathas under the leadership of Shivaji in 1677 AD. He recaptured it from the Bijapur sultans who had originally taken control of the fort from the Marathas.