Ireland: An Expansion through Time The Romans were the first true force to convert to Christianity. During their reign they would conquer and command heathen tribes into obeying this new found religion. However, the Roman Empire would decay, disappear and then it was left to another group to take over. The Irish would eventually become a driving force behind Christianity; peaceably converting and forming new ideas and thought behind the religion itself. Thus, the Irish unknowingly save civilization. To put things in perspective, first one must know some background information. For it was Augustine who brought about the need for explanations.