Complex sentence: The rebellion of Thomas Wyatt in February 1554 led to the execution of Guilford Dudley, but his brothers John, Ambrose, Robert and Henry remained imprisoned in a room of the Beauchamp Tower.
Split into simpler sentences: The rebellion of Thomas Wyatt in February 1554 led to the execution of Guilford Dudley. His brothers John, Ambrose, Robert, and Henry remained imprisoned in a room of the Beauchamp Tower.