The Axumite Kingdom, also known as the Aksum Kingdom, was an important trading nation in northeastern Africa, growing from circa the 5th century BC to become an important trading nation by the 1st century AD. It converted to Christianity in 325 or 328 (various sources).
It was founded by a mixture of people from Yemen and colonists and traders from Greece, who had established ports along the coast. Spreading Christian and Islamic influences eroded the kingdom between the 7th century and the 10th century. The kingdom was forced inland, becoming more African and less Middle Eastern. Its rulers were overthrown by the Zagwe dynasty in the twelfth century, but Yekuno Amlak, who killed the last Zagwe king and founded the Solomonid dynasty traced his ancestry to the last king of Aksum, Dil Na'od.
It was the centre of the Axumite Kingdom, which emerged around the time of the birth of Jesus and declined after the 7th century due to unknown reasons, but contributed to the shift of the power centre of the Ethiopian Empire further inland.
The kingdom of Axum had its own written language called Ge'ez, and also developed a distinctive architecture exemplified by giant obelisks, the oldest of which (though much smaller) date from 5,000-2,000 BC This kingdom was at its height under king Ezana, baptized as Abreha, in the 300s (which was also when it officially embraced Christianity).
Axum is considered to be the holiest city in Ethiopia and is an important destination of pilgrimages.
The Kingdom of Aksum at its height extended across portions of present-day Eritrea, northern Ethiopia, Yemen, southern Saudi Arabia northern Somalia, Djibouti, and northern Sudan.
Furthermore, in the early times of the kingdom, around 1700 years ago, giant Obelisks to mark King's (and nobles') tombstones (underground grave chambers) were constructed, the most famous of which is the Obelisk of Axum.
After this period, the Axumite kingdom was succeeded by the Zagwe dynasty in the eleventh century or twelfth century, although limited in size and scope.