Complex sentence: While the exact murderers are unknown, it was said that the English protestants were executed by the wrath of the O'Flaherty following the Irish uprising of 1641 and this event helped to lionize Britain's revenge on the island.
Split into simpler sentences: While the exact murderers are unknown, it was said that the English protestants were executed by the wrath of the O'Flaherty following the Irish uprising of 1641. This event helped to lionize Britain's revenge on the island.