In Memory of Sean Mac Díarmada 1916 Easter Rising Leader 1883 - 1916. Born in County Leitrim Sean Mac Díarmada was one of the leaders of the 1916 Easter Rising, a member of the Provisional Government and a Signatory to the 1916 Proclamation of the Irish Republic, he was executed by a British military firing squad in Kilmainham Gaol on 12th May 1916. This street (Sean MacDermott Street) is named in his honour. Beídhmuid ag cuímhneamh i gconaí orthu.