 His sister, Bridget "Bridie" Crowley, later O'Donnell, was a member of Cumann na mBan from the age of 14.In the week starting with Sunday, 23 April 1916, and including the Easter Rising of the 24 to 29 April, Peter served with the Ballylanders Company under the command of William P. Hanahan.Through this period, Peter made ammunition and cut communications lines in preparation for attack on Royal Irish Constabulary (R.I.C.)