The Spanish threat was readily dealt with, and FitzWilliam turned up the pressure on those Ulster lords who owed their allegiance to the Earl of Tyrone. One of these lords, the MacMahon, was put to death by royal authority in Monaghan town in 1591, and it became clear that the Dublin government was set on thoroughly curbing the power of the Gaelic leaders of Ulster. Although Tyrone continued to display his loyalty to the crown, the course had been set for a showdown and he went in to rebellion in 1595, at the start of the Nine Years War.