Although the history of Somalia is poorly studied, occasional researches show that the nation has a rich, ancient history. The purpose of this chapter is to explore the evolution of Somali society and aspects of their economy throughout circa 3000 BCE–500 CE. During 1960s–1980s, it has been postulated that the Somalis originated from the region of Omo-Tana around 1500 BCE and eventually expanded toward the north until 1400 CE. The chapter reassessed this hypothesis and further used new or less utilized data from linguistic, genetic, archeology, and ancient documentary sources. The integrated data suggest that the ancestral home of the Macro-Somali was the northern part of their Peninsula from about 3000 BCE and in due course, they expanded toward the south and west throughout 1500 BCE–500 CE. The data also explain the nature of their pre-Islamic socioeconomic system and their interaction with the Arabian-Mediterranean region upon which the Greco-Roman geographers of 150 BCE–550 CE elaborated.