Historically, aspects of the culture of the Arabian Peninsula were combined in various forms with the cultures of conquered regions and ultimately denominated Arab. After the rise of Islam in the Hejaz, Arab culture and language were spread outside the Arabian Peninsula through conquest, trade and intermarriages between members of the non-Arab local population and the peninsular Arabs. The Arabic language began to serve as a lingua franca in these areas and dialects were formed. Although Yemen is traditionally held to be the homeland of the Arabs, most of the Yemeni population in fact did not speak Old Arabic prior to the spread of Islam, but South Semitic languages instead.