Why did God allow RCC to grow?

Q: If Catholicism is a false religion, why has God allowed it to grow until today?

A: False Religions grow everywhere since long longgggg ago - after Eden. People gravitate to appearing religious but inside are full of sin. They do not seek truth but self. They worship self. 

God draws people to himself and saves people out of their sins and into righteousness thru Christ.

If you look at true history...

The truth is every town and city had a local church growing there under "Christianity" as it spread. The one in Rome according to Romans 1 had a large number of people. Those ones back then were of true Christianity. Rome controlled an empire region in that area and banned Christianity at some point. I am sure the true believers went underground then. In 325AD Constantine legalized it because he liked some ideas from Christianity. From sometime around then till  the 400s/500s serious false teachings entered in the church in Rome and in 606AD the religion of Roman Catholicism split from "the true Church" [all the redeemed in Christ] and RCC actually began. 

That new religion was one very diff from the NT church in the Bible times. They had (from somewhere in 300s to 500s) started adding heresy in their beliefs [and still do today] and are apostate. Only RCC priests in Roman controlled regions had access to the Bible then, and controlled what was known. Usually one Bible per church. The People couldnt look into it for truth or fact checking what priests or popes taught, that is ... until Reformers did. They exposed the false religion of RCC. Remember RCC was only those in the Roman Empire not the whole world. However Rome did conquer other nations over time, (and forced conversions)... but the Reformers got Bibles into the peoples hands and into their actual language. They restored biblical truth and the true gospel of salvation and true Christianity is in what today is called Protestantism. We protested against error, heresy, apostasy and their false gospel...by declaring & standing on truth (as God revealed it in the 66 books of Scripture; the special revelation of God to mankind). And always will. 

To examine and investigate Roman Catholic Religion 

What is the Biblical Gospel ?