3 When the impious Mohammedan power, trusting in its powerful fleet and war-hardened armies, threatened the peoples of Europe with ruin and slavery, then - upon the suggestion of the Sovereign Pontiff - the protection of the heavenly Mother was fervently implored and the enemy was defeated and his ships sunk. Thus the Faithful of every age, both in public misfortune and in private need, turn in supplication to Mary, the benignant, so that she may come to their aid and grant help and remedy against sorrows of body and soul. And never was her most powerful aid hoped for in vain by those who besought it with pious and trustful prayer.
Source: Ingravescentibus Malis (Vatican.va)