Until the thirteenth century, education within the Byzantine Greek population was more advanced than in the West, particularly at primary school level, resulting in comparatively high literacy rates. Success came easily to Byzantine Greek merchants, who enjoyed a very strong position in international trade. Despite the challenges posed by rival Italian merchants, they held their own throughout the latter half of the Byzantine Empire's existence. The clergy also held a special place, not only having more freedom than their Western counterparts, but also maintaining a patriarch in Constantinople who was considered the equivalent of the pope. This position of strength had built up over time, for at the beginning of the Byzantine Empire, under Emperor Constantine the Great (), only a small part, about 10%, of the population was Christian.