Bela reached the apogee of his political greatness in 1264 when, shortly after his crushing defeat of the Servian king, Stephen Urosh, he entertained at his court, at Kalocsa, the ambassadors of the newly restored Greek emperor, of the kings of France, Bulgaria and Bohemia and three Tatar mirzas.
The problem of determining an orbit may be regarded as coeval with Hipparchus, who, it is supposed, found the moving positions of the apogee and perigee of the moon's orbit.
A line joining the moon in perigee and in apogee is called the " line of apsides."
In the course of the next few months he gathered into his hands every branch of the government: he had reached the apogee of his short-lived greatness.
The task, however, was so gigantic that after 150 years of strenuous effort, at the period which may be considered as the apogee of its power, that is, in the first half of the 13th century, the papacy had attained only incomplete results.