Pope Peter IV succeeded Pope Theodosius I of Alexandria , who was the last to be recognised by both Oriental and Eastern Orthodox Churches as the Patriarch of Alexandria but was later Pope Theodosius was exiled by the orders of Emperor Justinian I because he did not agree with him on the resolutions of the Council of Chalcedon2. Pope Theodosius spent the last 28 years of his life imprisoned in Constantinople and after his death the Egyptians elected Peter IV as his successor 3