The eastern part of the Roman Empire held imperial power led by the city of Byzantium later renamed Constantinople in honor of Emperor Constantine (316). It remained the capital until Charlemagne revived the Western Empire (316). Between 324 and 330, “the Byzantine Empire passed from an initial period of expansion and splendor to a period of prolonged contradiction and fragmentation and, finally, to a catastrophic defeat” (316). The first period; between 324 and 632, Byzantine history experienced great territorial, political and cultural successes (317). Especially under the reign of Emperor Justinian and Empress Theodora; both smart and tough; to the point of being called tyrants by their court historian and biographer (317-18). During their reign there were more than 1500 cities, of which Constantinople was the largest, full of great size and splendor (317). Between the 4th and 5th centuries Decurioni; councils of 200 local, wealthy landowners governed the towns (318). In the 6th century, however, the councils of the decurions were replaced by special governors considered more reliable by the emperor (318). Justinian also ordered a revision of Roman law and created several compilations with the help of a committee of learned jurists (320, 342). The compilations later became the foundation of most European law (320). The first compilation; Codex, revised imperial edicts, the second; Novellae, presented the decrees issued by Justinian and his successors, the third; the Digest, collection of opinions of old jurists, and the fourth compilation; the Institutes, practical textbook for young scholars (320). However, this strengthening of the empire did not allow him to recover the western imperial lands conquered by the barbarians... middle of paper... their religion over the people (325). Therefore, these peoples found refuge in Muslims from Byzantine oppression (325). The Muslim conquerors tolerated other religions and offered protection to many peoples (326). Christian Europe developed an enduring fear and suspicion of Muslims as they were assailed and challenged by them on all fronts (326). In both the east and west the Muslim invasion was met and stopped although contact between Muslims and Christians continued (326). Muslims viewed Byzantium “as a model from which to learn and improve” (326). Despite the differences between the Christian West and the Muslim world, there was a creative exchange between the two (326). Because the Arabs were more advanced, the West benefited more from this interchange (326). Often, the Church became a major force for Western Europe through invasions, changes, etc. (328).