The ancient history of Yemen or South Arabia is especially important as one of the oldest centers of civilization in the Near East. Its relatively fertile land and adequate rainfall in a moister climate helped sustain a stable population, a feature recognized by the ancient Greek geographer Ptolemy, who described Yemen as Eudaimon Arabia (better known in its Latin translation, Arabia Felix) meaning Fortunate Arabia or Happy Arabia. Between the eighth century BCE and the sixth century CE, it was dominated by six main states which rivaled each other, or were allied with each other and controlled the lucrative spice trade: Saba', Ma'īn, Qatabān, Hadhramaut, Kingdom of Awsan, and the Himyarite Kingdom. Islam arrived in 630 CE and Yemen became part of the Muslim Caliphate.

The centers of the Old South Arabian kingdoms of present-day Yemen lay around the desert area called Ramlat al-Sab'atayn, known to medieval Arab geographers as Ṣayhad. The southern and western Highlands and the coastal region were less influential politically. The coastal cities were however already very important from the beginning for trade. Apart from the territory of modern Yemen, the kingdoms extended into Oman, as far as the north Arabian oasis of Lihyan (also called Dedan), to Eritrea, and even along coastal East Africa to what is now Tanzania.

Archaeology of Yemen

Sabaean Studies, the study of the cultures of Ancient South Arabia, belong to the younger branches of archaeology since in Europe ancient South Arabia remained unknown for much longer than other regions of the Orient. In 1504 a European, namely the Italian Lodovico di Varthema, first managed to venture into the interior. Two Danish expeditions contributed to by Johann David Michaelis (1717–1791) and Carsten Niebuhr (1733–1815) among others, contributed to scientific study, if only in a modest way.

In the first half of the 19th century other European travelers brought back over one hundred inscriptions. This stage of investigation reached its climax with the travels of the Frenchman Joseph Halévy 1869/70 and the Austrian Eduard Glaser 1882–1894, who together either copied or brought back to Europe some 2500 inscriptions. On the basis of this epigraphical material Glaser and Fritz Hommel especially began to analyse the Old South Arabian language and history. After the First World War excavations were finally carried out in Yemen. From 1926 Syrians and Egyptians also took part in the research into ancient South Arabia. The Second World War brought in a new phase of scientific preoccupation with ancient Yemen: in 1950–1952 the American Foundation for the Study of Man, founded by Wendell Phillips, undertook large-scale excavations in Timna and Ma'rib, in which William Foxwell Albright and Fr. Albert Jamme, who published the corpus of inscriptions, were involved. From 1959 Gerald Lankester Harding began the first systematic inventories of the archaeological objects in the then British Protectorate of Aden. At this time Hermann von Wissmann was particularly involved with the study of the history and geography of ancient South Arabia. In addition, the French excavations of 1975–1987 in Shabwah and in other locations, the Italian investigations of Paleolithic remains and the work of the German Archaeological Institute in the Ma'rib area are particularly noteworthy.

Written sources The body of source material for Old South Arabia is sparse. Apart from a few mentions in Assyrian, Persian, Roman and Arabic sources, as well as in the Old Testament, which date back to the 8th century BCE right up to the Islamic period, the Old South Arabian inscriptions are the main source. These are however largely very short and as a result limited in the information they provide. The predominant part of the inscriptions originates from Saba' and from the Sabaeo-Himyaritic Kingdom which succeeded it, the least come from Awsān, which only existed as an independent state for a short time. Most of the extant texts are building inscriptions or dedications; it is rare for historical texts to be found.

Chronology Although the Kingdom of Saba' already appears in Assyrian sources in the 8th century BCE, this benchmark is not sufficient to date the early history of ancient South Arabia, because the first absolutely reliable dating starts with the military campaign of Aelius Gallus in 25 BCE, and the mention of the king Ilasaros. For earlier times the chronology must be established on the basis of a comparison of the Old South Arabian finds with those from other regions, through palaeography, on the basis of the reconstructed sequence of kings and by radio carbon dating. Here two schools of thought have essentially evolved: the "Short Chronology" and the "Long Chronology". At the end of the 19th century Eduard Glaser and Fritz Hommel dated the beginning of the Old South Arabian Civilisation to the late 2nd millennium BCE, a dating that persisted for many years.

In 1955 Jacqueline Pirenne published a comparison of Old South Arabian and Greek art and came to the conclusion that the South Arabian Civilisation first developed in the 5th century BCE under Greek influence. She also supported this new "Short Chronology" by means of paleaeographic analysis of the forms Old South Arabian letters. Based on the American excavations in Timna and Ma'rib in 1951–52 another "Intermediary Chronology" came into being at about the same time, which merely set the beginning of Qatabān and Ma'īn at a later time than in the "Long Chronology". On the basis of the study of a rock inscription at Ma'rib ("Glaser 1703") A. G. Lundin and Hermann von Wissmann dated the beginning of Saba' back into the 12th or the 8th century BCE. Although their interpretation was later demonstrated to be partially incorrect, the "Short Chronology" has not been definitively proven, and in more recent times more arguments have been brought against it. Above all because of the results of new archaeological research, such as that carried out by the Italians in Yala / Hafari and by the French in Shabwah the "Long Chronology" attracts more and more supporters. Meanwhile, the majority of experts in Sabaean studies adhere to Wissman's Long Chronology, which is why the dates in this article have been adjusted in accordance with it.

Islamic accounts of pre-dynastic Qahṭān (3rd millennium BCE - 8th century BCE) According to medieval Muslim Arab historians, ancient Semitic-speaking peoples of South Arabia united as the Qahtanites. The Qahtanites in ancient times The Qahṭānites began building simple earth dams and canals in the Marib area in the Ramlat al-Sab'atayn. This area would later become the site of the Marib Dam.

A trade route began to flourish along the Red Sea coasts of Tihāmah. This period witnessed the reign of the legendary Queen of Sheba mentioned in the Bible, called Bilqīs by Muslim scholars. Queen Bilqis

At the end of this period, in the 9th century BCE, writing was introduced; this now meant that South Arabian history could be written down.

Archaeology and the prehistory of Yemen

The study of South Arabian prehistory is still at the beginning, although sites are known going back to the Palaeolithic. There are tumuli and megalithic enclosures dating back to the Neolithic. Immediately before the historical kingdoms in 2500, two Bronze Age cultures go out of North Yemen and from the coast of the Indian Ocean. In the middle of the second millennium BCE, the first important urban centers appear in the coastal area, among which are the sites of Sabir and Ma'laybah. So far, it has not been adequately explained whether the Old South Arabian Civilization of Yemen was a direct continuation from the Bronze Age, or if at the beginning of the Iron Age groups of people began wandering south from Palestine or North Arabia, as is partly conjectured.

Documented history It is not yet possible to specify with any certainty when the great South Arabian Kingdoms appeared; estimates range (within the framework of the long chronology) from the 12th until the 8th century BCE.

Kingdom of Saba (12th century BCE – 275 CE)

During Sabaean rule, trade and agriculture flourished generating much wealth and prosperity. The Sabaean kingdom was located in what is now the 'Asīr region in southwestern Saudi Arabia, and its capital, Ma'rib, is located near what is now Yemen's modern capital, Sana'a. According to Arab tradition, the eldest son of Noah, Shem, founded the city of Sana’a, which is also called the city of Sam, or also called Azal city, which means the ancient city.

Sabaean hegemony (800 BCE – 400 BCE) At the time of the earliest historical sources originating in South Arabia the territory was under the rule of the Kingdom of Saba', the centres of which were situated to the east of present-day Sana'a in Ṣirwāḥ and Ma'rib. The political map of South Arabia at that time consisted of several larger kingdoms, or rather tribal territories: Awsān, Qatabān and the Ḥaḑramawt; and on the other hand an uncertain number of smaller states, such as the city states of Ḥaram and Nashaq in al-Jawf. Shortly after, Yitha'amar Watar I had united Qatabān and some areas in al-Jawf with Saba', the Kingdom reached the peak of its power under Karib'il Watar I, who probably reigned some time around the first half of the 7th century BCE, and ruled all the region from Najrān in the south of modern South Arabia right up to Bāb al-Mandab, on the Red Sea. The formation of the Minaean Kingdom in the river oasis of al-Jawf, north-west of Saba' in the 6th century BCE, actually posed a danger for Sabaean hegemony, but Yitha'amar Bayyin II, who had completed the great reservoir dam of Ma'rib, succeeded in reconquering the northern part of South Arabia. Between the 8th and 4th centuries the state of Da'amot emerged, under Sabaean influence in Ethiopia, which survived until the beginning of the Christian era at the latest. The exact chronology of Da'amot and to what extent it was politically independent of Saba' remains in any case uncertain.

The success of the Kingdom was based on the cultivation and trade of spices and aromatics including frankincense and myrrh. These were exported to the Mediterranean, India, and Abyssinia where they were greatly prized by many cultures, using camels on routes through Arabia, and to India by sea. Evidence of Sabaean influence is found in northern Ethiopia, where the South Arabian alphabet, religion and pantheon, and the South Arabian style of art and architecture were introduced. The Sabaeans created a sense of identity through their religion. They worshipped El-Maqah and believed that they were his children. For centuries, the Sabaeans controlled outbound trade across the Bab-el-Mandeb, a strait separating the Arabian Peninsula from the Horn of Africa and the Red Sea from the Indian Ocean.

Agriculture in Yemen thrived during this time due to an advanced irrigation system which consisted of large water tunnels in mountains, and dams. The most impressive of these earthworks, known as the Ma'rib Dam was built c. 700 BCE, provided irrigation for about 25,000 acres (101 km²) of landCulture of Yemen - History and ethnic relations, urbanism, architecture, and the use of space and stood for over a millennium, finally collapsing in 570 CE after centuries of neglect. The final destruction of the dam is noted in the Qur'an and the consequent failure of the irrigation system provoked the migration of up to 50,000 people.

The Sabaean kingdom, with its capital at Ma'rib where the remains of a large temple can still be seen, thrived for almost 14 centuries. This kingdom was the Sheba described in the Old Testament.

Kingdom of Ḥaḑramawt (8th century BCE – 300 CE)