South Arabia also known as Greater Yemen is a historical region that consists of the southern region of the Arabian Peninsula, mainly centered in what is now the Republic of Yemen, yet it has also historically included Najran, Jizan, and 'Asir, which are presently in Saudi Arabia, and the Dhofar of present-day Oman.
South Arabia is inhabited by people possessing distinctive linguistic and ethnic affinities, as well as traditions and culture, transcending recent political boundaries. There are two indigenous language groups: the now extinct Old South Arabian languages and the unrelated Modern South Arabian languages, both members of the Semitic family.
The term Yamnat was mentioned in Old South Arabian inscriptions on the title of one of the kings of the second Himyarite kingdom known as Shammar Yahrʽish II. The term was probably referring to the southwestern coastline of the Arabian peninsula and the southern coastline between Aden and Hadramout. One etymology derives Yemen from ymnt, meaning "South", and significantly plays on the notion of the land to the right (𐩺𐩣𐩬). Other sources claim that Yemen is related to yamn or yumn, meaning "felicity" or "blessed", as much of the country is fertile. The Romans called it Arabia Felix (fertile Arabia), as opposed to Arabia Deserta (deserted Arabia). Classical Latin and Greek writers used the name "India" to refer to South Arabia (ancient Yemen). The use of the term "India" arose from the fact that the Persians called the Abyssinians whom they came into contact in South Arabia by the name of the dark-skinned people who lived next to them, i.e., Indians.
Three thousand years ago, several ancient states occupied the region of South Arabia, being M'ain, Qataban, Hadhramaut, and Saba. In these ancient times South Arabia claimed several notable features: the famous dam at Marib, the cosmopolitan incense trade, as well as the legendary Queen of Sheba. Two thousand years ago the Himyarites became the masters of South Arabia, dominating the region for several centuries. The Ethiopian Kingdom of Aksum invaded South Arabia first in the 3rd–4th centuries, then later in the 6th under King Kaleb who subjugated the region, c. 520. They were displaced by Persian forces of the Sassanid dynasty, c.575, who also arrived by sea. A half-century later, in the year 6 A.H. (628), the region converted to Islam.