This chapter is an introduction to the change in ecology, which happened because of the new faith and the migration of the Arabs out of their peninsula in large and fairly organized numbers. I hope to spread out both the linguistic structure and non-linguistic situation after the emergence of Islam and the start of the Arab conquests. In this introductory chapter, I introduce the global communicative linguistic changes Islam brought about on the shape and perception of the language in general, such as the unification of the dialects into a more inclusive mental entity for the first time, comprising the Arabic tongue. I will also discuss the role of the Qur’ān in taking the pre-Classical variety towards the everyday use of the language and elevating it to the position of a prestigious model. I will then introduce the effect of the conquests in bringing Arabic to the regions of the Middle East. To do this, I will focus on the nature of the conquests, the establishment of garrison towns and the manner of communication between Arabs and non-Arabs in these towns. I will then introduce the socio-demographic features of the conquered territories before and on the eve of the Arab conquests, which are extremely important in the arabicization process.