Complex sentence: In 1402 Douglas'brother-in-law, the heir to the throne, David Stewart, Duke of Rothesay was held in close arrest, first at the Bishop's Palace at St Andrews, then at the Royal Palace of Falkland.
Split into simpler sentences: In 1402 Douglas'brother-in-law, the heir to the throne, David Stewart, Duke of Rothesay was held in close arrest. First at the Bishop's Palace at St Andrews, then at the Royal Palace of Falkland.