670-689 Rome Argues Theology While Islam Advances

In this twenty year period the ruling powers in Rome and Constantinople sat around arguing about theology while the Islamic tide advanced throughout the east, the Lombards strengthened their position in Europe and plague ravaged England in 685.

This time, theological controversy was Monothelitism -- the belief that Christ did not possess simultaneously a divine will and a human will, but only one that he exercised through both his divine and human natures -- first put forward by Pope Honorius I in 625.

Emperor Constantine IV wanted to ban Monothelitism -- as did the Pope Agatho (678-681) -- and it was duly put to rest at the Council of Constantinople in 680.

By 680, the empire was forced to recognize the Lombard Kingdom in Italy, and the conversion of the Lombards to Catholicism made their rule more acceptable to the ruling class (represented by the bishop of Rome)

Another ramification of theological oblivion of this period that allowed the Islamic advance was that Rome gained supremacy over Constantinople. Only four of the next sixteen popes would come from Rome, the rest would come from eastern areas lost to Islam.

Also, the election of popes from Leo II onwards came to be subject to the emperor's approval rather than that of Constantinople.