The Roman Empire, also known as Res Publica Romana or Imperium Romanum or Senatus Populusque Romanus (SPQR), was one of the most important civilizations of the world history. The Roman Empire succeeded the 500 year old Roman Republic (510 BC - 1st century BC) and ruled a large territory between 27 BC - 1453 AD (approximately 5,9 million square kilometers, or 2,3 million square miles).
The Roman Empire was divided in the 4th century AD into East and West. The Western Roman Empire fell apart in the 5th century AD. The Eastern Roman Empire, known as Byzantine Empire after emperor Constantine, collapsed with the conquest of Constantinople (modern Istanbul) by the Ottomans in the 15th century AD.
The Romans knew the importance of Asia Minor because it formed a natural land-bridge between East and West in terms of trade routes, culture, agriculture and military. After Alexander the Great and many other small Anatolian kingdoms, Romans captured Asia Minor after the 2nd century BC and ruled it for many centuries. They first set their foot in Anatolia in 190 BC after defeating King Antiochus III of Seleucia in Magnesia. Then after the death of Attalos III of Pergamon Empire in 133 BC, they established the province of Asia Minor with Ephesus as its capital.
During the Pax Romana period (Roman Peace), trade and culture was increased in Asia Minor. Many ancient cities flourished and became important commercial and cultural centers in this part of the world. Roman emperors such as Augustus, Hadrian, Trajan, etc. they all traveled here and helped to the development of the province. Great Roman cities were built in Anatolia during the Roman period; Aphrodisias, Ephesus, Perge and Aspendos were some of the most important of the Roman cities in Asia Minor, amongst hundreds of others. Excellent Roman road network connected these cities with the rest of the Empire, many colossal temples and public works (libraries, fountains, suege systems etc) were built by the architects.
Also, a new religion spread in Anatolia during the reign of the Roman Empire; the Christianity. Early Christians, escaping from the Roman persecutions, settled in Antioch (modern Hatay), Iconium (modern Konya), Ephesus, Cappadocia and so on. Saint Paul made his journeys in Asia Minor in order to spread the word, finally becoming the official religion of the Eastern Roman Empire.
At its zenith, the Roman Empire included these today's countries and territories: most of Europe (England, Wales, Portugal, Spain, France, Italy, Austria, Switzerland, Luxembourg, Belgium, Gibraltar, Romania, Moldova, Ukraine), coastal northern Africa (Libya, Tunisia, Algeria, Morocco, Egypt), the Balkans (Albania, Greece, Hungary, Bosnia, Slovenia, Croatia, Bulgaria, Turkey), the Mediterranean Sea, the Black Sea, Asia Minor, and some parts of Mesopotamia and the Middle East (Syria, Lebanon, Iraq, Jordan, Israel).