WORLDS APART BECOME ACQUAINTED (5TH-8TH CENTURIES)
The pre-Islamic and early Islamic Arabs of the fifth to the early seventh centuries were active in a variety of environments, including western Persia, Mesopotamia, Syria, Palestine, the Arabian Peninsula, as well as the regions bordering on Egypt and Ethiopia. Ethnic, religious, political, military, and commercial ties linked them with surrounding societies, resulting in a variety of ways of life, cultural orientations, and identities.
Before the sixth century, it is difficult to detect a homogeneous ethnic, social, religious, cultural, or political entity that can be clearly defined as Arab.2 Instead of imposing this ethnonym on ancient groups that may have regarded themselves otherwise  or seeking for the origins of Arab ethnicity in an ancient warrior elite,  most specialists point to a shared linguistic and cultural heritage as the common basis of different Arab groups. Compared by some to ethnic processes in the Germanic sphere of Late Antiquity and the early Middle Ages,5 the transformation of political constellations and tribal affiliations led to the explicit formulation of an overriding Arab identity in the three centuries leading up to the rise of Islam. At the eve of Islam, Arab groups of the Arabian Peninsula were neither stable nor, strictly speaking, ‘ethnic’, but subject to constant reconfiguration, processes in which the construction of genealogies and accounts of origin played an important role. Islam’s prophet Muhammad managed to unite the tribes of the Arabian Peninsula for the first time, becoming, in the words of Patricia Crone, ‘the creator of a people’. With great difficulties, Muhammad’s successor Abu Bakr managed to retain control over these groups during his caliphate (10-12/632-34). Thanks to the Muslim seizure of the Middle East in the following decades, Arab groups beyond the peninsula were integrated into the folds of the emerging Arabic- Islamic world. 
Because of the rise of Islam, the Arab world emerged as a comparatively cohesive force capable not only of radically remodelling, but also of systematically describing its environment in writing. When the fusion of Arab groups under the guiding force of Islam was consolidated in the century following Muhammad’s death,n this process of ethno-cultural condensation led to the formulation of a specifically Arabic-Islamic identity with a corresponding cultural memory. Deeply rooted in Arab history, the written record left behind by Arabic-Islamic scholars preserves much that had been characteristic of the pre-Islamic age. Nonetheless, Arabic- Islamic records on the pre-expansionist Arab world tend to obscure that Arab groups had long been an integral part of a late antique Middle Eastern landscape well connected to the western Mediterranean. In consequence, it is necessary to discuss to what extent the ‘Islamization’ of the pre-Islamic Arabs’ cultural memory modified existing pre-Islamic Arab knowledge about the Mediterranean’s northwestern shores or even entailed its loss.12
-  Trimingham, Christianity (1979), p. 1; Bowersock, Arabia (1994), p. 1; Hainthaler, Araber (2007),p. 12; Hoyland, Arabia (2003), pp. 13—84; Fisher, Empires (2011).
-  Millar, East (1993), pp. 10—11, 221, 227, 306, 331, 333, 402, 512, constantly refers to the difficulties of identifying Arabs’, of distinguishing between Arabs’ and others. See scholarly definitionsof Arab’ in Retso, Arabs (2003), pp. 105—18.
-  Shahid, Rome (1984), p. ix. 4 Retso, Arabs (2003), pp. 623—5.
-  5 Guidetti, Vivere (2007), pp. 23—7, 57—61, 215—20, 230, 287—94; Fisher, Empires (2011), pp. 5,
-  23—4, 80—3, 170. On ethnic processes in the late antique and early medieval ‘Germanic’ world, seePohl, Volkerwanderung (2002).
-  Hoyland, Arabia (2003), pp. 229—47, esp. 230—1; Hoyland, ‘Epigraphy’ (2007), pp. 219—42;Robin, ‘Antiquite’ (2010), pp. 81—99, esp. 85—92; Hoyland, ‘Kings’ (2009), pp. 374—400.
-  Donner, Conquests (1981), pp. 20—6.
-  Crone, Trade (1987/2004), p. 237; Donner, Conquests (1981), p. 49.
-  Donner, Conquests (1981), pp. 51—90; Abd Allah Karir, harakat (2006).
-  Kaegi, Byzantium (1995), pp. 269—72; Shahid, ‘Ghassan’ (1965), p. 1020.
-  Cf. Duri, Formation (1987), p. 29. 12 Lewis et al., ‘al-Djahiliyya’ (1965), p. 383.