Monck proved his loyalty to Parliament by refusing to take part in the Second English Civil War and requiring all his officers to sign a declaration of support. However, his position in Ulster became extremely precarious following the Execution of Charles I in January 1649, since it was dominated by Scots Presbyterian settlers, supported by a Covenanter army under Robert Monro. The Scots not only objected to the English killing their king without consultation but as Calvinists viewed monarchy as divinely ordained, making it also sacrilegious. As a result, they defected to the Royalist-Confederate alliance led by Ormond and in desperation, Monck agreed to a secret truce with Eoghan Ó Néill, the Catholic leader in Ulster, which he did not communicate to Parliament until May.