History of the Roman Empire
Theodosius was the last Emperor who ruled over the whole Empire. After his death in 395, he gave the two halves of the Empire to his two sons Arcadius and Honorius; Arcadius became ruler in the East, with his capital in Constantinople, and Honorius became ruler in the West, with his capital in Milan and later Ravenna. The Roman state would continue to have two different emperors with different seats of power throughout the 5th century, though the Eastern Romans considered themselves to be the only ones who were fully Roman. Latin was used in official writings as much as, if not more than, Greek and the two halves were nominally, culturally and historically, if not politically, the same state.
Roman expansion in Italy
The last king of Rome, Tarquinius Superbus, is portrayed by the sources as a powerful, but tyrannical, king. He is said to have taken Pometia by storm and Gabii by ruse, colonized Signia and Circeii, and to have organized the Latin states into an alliance under his own leadership. However Tarquinius was deposed by a conspiracy led by two of his relatives, Lucius Junius Brutus and Lucius Tarquinius Collatinus. These two then founded the Roman Republic with themselves as its first two consuls; traditionally the overthrow of the monarchy has been dated to 509 BC. Tarquinius is supposed to have sought refuge with king Lars Porsenna of Clusium, who marched against Rome to reinstate the king. After various heroic acts by brave defenders of Rome, Porsenna gave up and instead attacked Aricia, but was defeated by an alliance of Latin cities and the Greek colony of Cumae. Modern historians have had difficulties accepting this tale and have instead proposed that Porsenna actually captured Rome and deposed Tarquinius and replaced him with two leading aristocrats. With leadership of the city divided, Rome would have been easier for Porsenna to control.