<P> The empire in the East--often known as the Byzantine Empire, but referred to in its time as the Roman Empire or by various other names--had a different fate . It survived for almost a millennium after the fall of its Western counterpart and became the most stable Christian realm during the Middle Ages . During the 6th century, Justinian I reconquered Northern Africa and Italy . But within a few years of Justinian's death, Byzantine possessions in Italy were greatly reduced by the Lombards who settled in the peninsula . In the east, partially resulting from the destructive Plague of Justinian, the Romans were threatened by the rise of Islam, whose followers rapidly conquered the territories of Syria, Armenia and Egypt during the Byzantine - Arab Wars, and soon presented a direct threat to Constantinople . In the following century, the Arabs also captured southern Italy and Sicily . Slavic populations were also able to penetrate deep into the Balkans . </P> <P> The Romans, however, managed to stop further Islamic expansion into their lands during the 8th century and, beginning in the 9th century, reclaimed parts of the conquered lands . In 1000 AD, the Eastern Empire was at its height: Basil II reconquered Bulgaria and Armenia, culture and trade flourished . However, soon after, the expansion was abruptly stopped in 1071 with the Byzantine defeat in the Battle of Manzikert . The aftermath of this important battle sent the empire into a protracted period of decline . Two decades of internal strife and Turkic invasions ultimately paved the way for Emperor Alexios I Komnenos to send a call for help to the Western European kingdoms in 1095 . </P> <P> The West responded with the Crusades, eventually resulting in the Sack of Constantinople by participants in the Fourth Crusade . The conquest of Constantinople in 1204 fragmented what remained of the Empire into successor states, the ultimate victor being that of Nicaea . After the recapture of Constantinople by Imperial forces, the Empire was little more than a Greek state confined to the Aegean coast . The Roman Empire finally collapsed when Mehmed the Conqueror conquered Constantinople on 29 May 1453 . </P> <P> The Roman Empire was one of the largest in history, with contiguous territories throughout Europe, North Africa, and the Middle East . The Latin phrase imperium sine fine ("empire without end") expressed the ideology that neither time nor space limited the Empire . In Vergil's epic poem the Aeneid, limitless empire is said to be granted to the Romans by their supreme deity Jupiter . This claim of universal dominion was renewed and perpetuated when the Empire came under Christian rule in the 4th century . In addition to annexing large regions in their quest for empire - building, the Romans were also very large sculptors of their environment who directly altered their geography . For instance, entire forests were cut down to provide enough wood resources for an expanding empire . In his book Critias, Plato described that deforestation: where there was once "an abundance of wood in the mountains," he could now only see "the mere skeleton of the land ." </P>

When was rome founded and when did it fall