are all modern states and became significant as distinct political entities after the fall and defeat and dissolution of the Ottoman Empire (1908–1922). Identity Arab identity is defined independently of religious identity, and pre-dates the spread of Islam, with historically attested Arab Christian kingdoms and Arab Jewish tribes. Today, however, most Arabs are Muslim, with a minority adhering to other faiths, largely Christianity, but also Druze and Baháʼí. Paternal descent has traditionally been considered the main source of affiliation in the Arab world when it comes to membership into an ethnic group or clan. Today, the main unifying characteristic among Arabs is Arabic, a Central Semitic language from the Afroasiatic language family. Modern Standard Arabic serves as the standardized and literary variety of Arabic used in writing. The Arabs are first mentioned in the mid-ninth century BCE as a tribal people dwelling in the central Arabian Peninsula subjugated by Upper Mesopotamia-based state of Assyria. The Arabs appear to have remained largely under the vassalage of the Neo-Assyrian Empire (911–605 BCE), and then the succeeding Neo-Babylonian Empire (605–539 BCE), Persian Achaemenid Empire (539–332 BCE), Greek Macedonian/Seleucid Empire and Parthian Empire. Arab tribes, most notably the Ghassanids and Lakhmids begin to appear in the south Syrian deserts and southern Jordan from the mid 3rd century CE onwards, during the mid to later stages of the Roman Empire and Sasanian Empire. Also, before them the Nabataeans of Jordan and arguably the Emessans, Edessans, and Hatrans all appear to have been an Aramaic speaking ethnic Arabs who came to rule much of the pre-Islamic fertile crescent often as vassals of the two rival empires, the Sasanian (Persian) and the Byzantine (Eastern Roman). Thus, although a more limited diffusion of Arab culture and language was felt in some areas by these migrant minority Arabs in pre-Islamic times through Arabic-speaking Christian kingdoms and Jewish tribes, it was only after the rise of Islam in the mid-7th century that Arab culture, people and language began their wholesale spread from the central Arabian Peninsula (including the south Syrian desert) through conquest and trade. Subgroups Arabs in the narrow sense are the indigenous Arabians who trace their roots back to the tribes of Arabia and their immediate descendant groups in the Levant and North Africa. Within the people of the Arabian Peninsula, distinction is made between: "Perishing Arabs" (), which are ancient tribes about whose history little is known.