12 The Hungarians have always striven to keep their kingdom bound as closely as possible to the Apostolic See as its "very own and most devoted possession." The register of public proceedings records many proofs of this, whether in the form of letters written by kings and nobles to the Roman pontiffs, or in the form of examples of heroic and energetic virtue which assisted the Church to protect its rights or to avenge its loss of rights on its enemies. This was even before the struggle began against the invading forces of the Moslems. The relationship of mutual service between King Louis the Great and Innocent VI and Urban V indicate this. And when Paul II urgently requested that the Catholic cause should be given strong help against the attack of the Hussites in Bohemia, King Mathias replied: "I have dedicated myself and my kingdom entirely to the Holy Roman Church and to your Beatitude. The Vicar of God on earth, nay, God Himself, cannot command any deed so difficult for me, or any so dangerous, that I should not think it dutiful and salutary to undertake, that I should not fearlessly attempt, especially when it is a case of strengthening the Catholic faith and crushing the perfidy of the impious .... Whatever enemies of religion it is necessary to meet in battle, behold, Mathias together with Hungary ... remain devoted to the Apostolic See and to your Beatitude and will remain so for ever." And the event did not fall short of the words of the king nor of the Pope's expectation; and it remains an evidence of great importance for later times.
Source: Insignes (Vatican.va)