Arab tribes, most notably the Ghassanids and Lakhmids, begin to appear in the southern Syrian Desert from the mid 3rd century CE onward, during the mid to later stages of the Roman and Sasanian empires.Before the expansion of the Rashidun Caliphate (632–661), "Arab" referred to any of the largely nomadic and settled Semitic people from the Arabian Peninsula, Syrian Desert, North and Lower Mesopotamia.
Today, "Arab" refers to a large number of people whose native regions form the Arab world due to the spread of Arabs and the Arabic language throughout the region during the early Muslim conquests of the 7th and 8th centuries and the subsequent Arabisation of indigenous populations.
The Arabs forged the Rashidun (632–661), Umayyad (661–750) and the Abbasid (750–1258) caliphates, whose borders reached southern France in the west, China in the east, Anatolia in the north, and the Sudan in the south.
Arab Muslims primarily belong to the Sunni, Shiite, Ibadi, Alawite, Druze and Ismaili denominations.
Arab Christians generally follow one of the Eastern Christian Churches, such as the Maronite, Coptic Orthodox, Greek Orthodox, Greek Catholic or Chaldean churches. The earliest documented use of the word "Arab" to refer to a people appears in the Kurkh Monoliths, an Akkadian language record of the ninth century BCE Assyrian conquest of Aram, which referred to Bedouins of the Arabian Peninsula under King Gindibu, who fought as part of a coalition opposed to Assyria.
Many of the Qedarite queens were also described as queens of the aribi.
The Hebrew Bible occasionally refers to Aravi peoples (or variants thereof), translated as "Arab" or "Arabian." The scope of the term at that early stage is unclear, but it seems to have referred to various desert-dwelling Semitic tribes in the Syrian Desert and Arabia.
The study of Pre-Islamic Arabia is important to Islamic studies as it provides the context for the development of Islam.
Some of the settled communities in the Arabian Peninsula developed into distinctive civilizations.
The Arab world stretches around 13 million km, from the Atlantic Ocean in the west to the Arabian Sea in the east, and from the Mediterranean Sea in the north to the Horn of Africa and the Indian Ocean in the southeast.