Why was the execution of the Irish leaders after the Easter Rising in 1916 key to the ultimate success of the rising?

by RivenCenturion

What did the execution of them actually achieve? What were the knock-on effects of the people switching support against the rebels, to the rebels?

d_paulson

It's my understanding that the execution created martyrs, and Eamon de Valera was spared given his American citizenship among other factors. He went on to become a unifying force in the Irish resistance.