In the 8th century the Empire was losing ground both in territory and people to the Islamic Arabs.
Some kind of revision of how Christianity was conducted and worshipped was thought needed to lessen the impact of Islam upon Asia Minor.
If carried out successfully perhaps the Empire in brighter times could retake Syria and even Egypt?

All these reforms did not make sense to the far western provinces of Italy, they did not know of the Islamic impact and merely thought the reforms were just another example of the tyranny of Constantinople upon poor old Rome.
So Italy rebelled and it was from this time that Venice became autonomous.

This was the 8th century.

The Great Schism of 1054AD was due to Western Imperialism married to the Papacy versus the Roman Empire and the Patriarchates.
The idea of having to confer to codes set out in Constantinople was not something the Franks liked, and by that time the Pope and candidates for the Papacy were of Frankish origin.

Then again none of the Papal representatives at Constantinople at the time were acting under offical Papal recognition and so the 'Curses' were empty.

It seems as the Empire could no longer rule by strength and wealth lands it had ruled in the 4th century, the Church network was left in the west to work out its own destiny not following edicts set out in Constantinople or other eastern cities.
So that by the 11th century it was the Church that often ruled the Emperors.

However one reason for the schism was political in that the Papacy was worried about military intervention in Italy by the Byzantines, such as the Sicilian project of Basil II, revived by Constantine IX and the 12th century campaigns by Manuel Comnenus.