From the Catholic Church's perspective, the ecclesiological issues are the central issue, which is why they characterize the split between the two churches as a schism. In their view, the Eastern Orthodox are very close to them in theology, and the Catholic Church does not consider the Orthodox beliefs to be heretical. However, from the perspective of Orthodox theologians, there are theological issues that run much deeper than just the theology around the primacy of the Pope. In fact, unlike the Catholics, who do not generally consider the Orthodox heretical and speak instead about the Eastern "schism", some prominent Orthodox theologians do consider the Catholic Church to be heretical on fundamental doctrinal issues of theology, such as the "Filioque". These issues have a long history as can be seen in the 11th-century works of Orthodox theologian and Saint Nikitas Stithatos.