Small correction. It wasn't the only organized church. The Catholics had already split away from the Eastern Orthodox in 1054.
I suggest you do further study as you keep repeating this falsehood. Out of curiosity -I would like to review your source for this false information? No source -no legitimacy...
Regardless, FYI for future reference I recommend you check for and avoid anti-Catholic sources of information -there are at a minimum as many of these anti-Catholic sources of information as there are other religions. Consequently, research from legitimate unbiased sources is best if seeking truth (for some reason there is much anti-Catholic propaganda).
Prior to beginning research into this specically I would suggest you consider the pretext of Latin versus Greek and the five patriarchates leading up to the time of the great schism which comprised Rome, Constantinople, Alexandria, Antioch, and Jerusalem with Rome the historically documented and established primacy.
Following this I suggest it would be prudent to find out specifically why Caerularius was excommunicated and why and when the remaining Eastern patriarchs went into schism thereby separating themselves from the (Latin) supreme pontiff in Rome.