First of all, stating that Roman Catholicism dates back 2000 years is not a correct statement. Christianity dates back to the first century is the correct way of saying it. Hence, BC (before Christ or before Christian era) and AD (Anno Domini or after the Christian era). The Church of Rome was not the only Christian church. Claiming age however impressive it may sound at first, doesn't prove much as despite its complexity Hinduism is not only one of the numerically largest, but also the oldest living major tradition on earth, with roots reaching back into the prehistory.
The protestant movement is said to have started in the sixteenth century, but we know that Luther and others that broke away from the Catholic Church did so because they believed the Roman Catholic Church had strayed from the truth of the Gospel.
The Church of Rome was not the only Christian church. In the 1st, 2nd, 3rd centuries - up until the split with the Orthodox, there was only one christian church - the Catholic Church. If you know otherwise, plese name them.