At its height, the Roman Empire covered much of Europe, including areas that would become Portugal, Spain, Andorra, England, France, Monaco, Luxembourg, Belgium, the Netherlands, Germany, Switzerland, Liechtenstein, Italy, San Marino, Malta, Austria, Slovenia, Croatia, Bosnia-Herzegovina, Hungary, Albania, Greece, Macedonia, Romania, Bulgaria, Turkey and Armenia. It also included territory in the Middle East and Africa that later became Syria, Iraq, Cyprus, Lebanon, Jordan, Israel, Egypt, Libya, Tunisia, Algeria and Morocco.
The Roman Empire also annexed some outlying areas. Portions of what would later become the Czech Republic, Slovakia, Georgia, Azerbaijan, Kuwait, Saudi Arabia and Sudan were at one time administered by the empire.
The empire began in 27 B.C. when the Roman Senate formally granted Octavian, Julius Caesar's adopted son, greater power and the new title Augustus, effectively ending the Roman Republic. It reached its height in the year A.D. 117. By the third century, the overextended empire struggled to handle invasions, civil unrest and economic uncertainty.
Emperor Diocletian was able to stem the empire's decline somewhat, partially by refusing absolute power and splitting the empire first in half and then into four regions between A.D. 286 and 293. The Western Roman Empire fell when Romulus Augustus was deposed in A.D. 476 , while the Eastern Roman Empire evolved into the Byzantine Empire, lasting until 1453, when the Ottomans took Constantinople.