Ladislaus was now thirteen years of age.  The most learned men of the age were appointed as his teachers, and he pursued his studies with great vigor.  Count Cilli, however, an ambitious and able man, soon gained almost unlimited control over the mind of his young ward, and became so arrogant and dictatorial, filling every important office with his own especial friends, and removing those who displeased him, that general discontent was excited and conspiracy was formed against him.  Cilli was driven from Vienna with insults and threats, and the conspirators placed the regency in the hands of a select number of their adherents.

While affairs were in this condition, John Hunniades, as regent, was administering the government of Hungary with great vigor and sagacity.  He was acquiring so much renown that Count Cilli regarded him with a very jealous eye, and excited the suspicions of the young king that Hunniades was seeking for himself the sovereignty of Hungary.  Cilli endeavored to lure Hunniades to Vienna, that he might seize his person, but the sagacious warrior was too wily to be thus entrapped.

The Turks were now in the full tide of victory.  They had conquered Constantinople, fortified both sides of the Bosporus and the Hellespont, overrun Greece and planted themselves firmly and impregnably on the shores of Europe.  Mahomet ii. was sultan, succeeding his father Amurath.  He raised an army of two hundred thousand men, who were all inspired with that intense fanatic ferocity with which the Moslem then regarded the Christian.  Marching resistlessly through Bulgaria and Servia, he contemplated the immediate conquest of Hungary, the bulwark of Europe.  He advanced to the banks of the Danube and laid siege to Belgrade, a very important and strongly fortified town at the point where the Save enters the great central river of eastern Europe.

Such an army, flushed with victory and inspired with all the energies of fanaticism, appalled the European powers.  Ladislaus was but a boy, studious and scholarly in his tastes, having developed but little physical energy and no executive vigor.  He was very handsome, very refined in his tastes and courteous in his address, and he cultivated with great care the golden ringlets which clustered around his shoulders.  At the time of this fearful invasion Ladislaus was on a visit to Buda, one of the capitals of Hungary, on the Danube, but about three hundred miles above Belgrade.  The young monarch, with his favorite, Cilli, fled ingloriously to Vienna, leaving Hunniades to breast as he could the Turkish hosts.  But Hunniades was, fortunately, equal to the emergence.

A Franciscan monk, John Capistrun, endowed with the eloquence of Peter the Hermit, traversed Germany, displaying the cross and rousing Christians to defend Europe from the infidels.  He soon collected a motley mass of forty thousand men, rustics, priests, students, soldiers, unarmed, undisciplined, a rabble rout, who followed him to the rendezvous where Hunniades had succeeded in collecting a large force of the bold barons and steel-clad warriors of Hungary.  The experienced chief gladly received this heterogeneous mass, and soon armed them, brought them into the ranks and subjected them to the severe discipline of military drill.