Complex sentence: Emmet was unable to secure the help of Michael Dwyer's Wicklow rebels, and many Kildare rebels who had arrived turned back due to the scarcity of firearms they had been promised, but the rising went ahead in Dublin on the evening of 23 July 1803.
Split into simpler sentences: Emmet was unable to secure the help of Michael Dwyer's Wicklow rebels. Many rebels from Kildare turned back due to the scarcity of firearms they had been promised, but the rising went ahead in Dublin on the evening of 23 July 1803.