St. Stephen of Hungary was crowned king by Pope Sylvester II in 1000 A.D. after Stephen consolidated his rule over competing tribal chieftains and allied with Christianity as a unifying dimension of his kingdom. He later founded many monasteries and built churches emphasizing liturgical and faithful unity with the papacy.
Since the early days of the church, the question of the use of force by Christian leaders has been a thorny one. St. Augustine's City of God famously dealt with the issue and much later, Martin Luther had more to say on the subject. The days of papal armies are long gone, the pope wielding moral authority more than worldly power. What are the legitimate uses of force, including lethal force, against evil? This question still prompts vigorous discussion.