Eritrea officially the State of Eritrea, is a country in the Horn of Africa. Eritrea is the Italian form of the Greek name (Erythra), meaning 'red [land]'. The capital is Asmara. It is bordered by Sudan in the west, Ethiopia in the south, and Djibouti in the southeast. The northeast and east of the country has an extensive coastline on the Red Sea, directly across from Saudi Arabia and Yemen. The Dahlak Archipelago and several of the Hanish Islands are part of Eritrea. Eritrea's size is approximately 117,600 km (45,406 sq mi) with an estimated population of 6 million. The Kingdom of Aksum, covering much of modern-day Eritrea and northern Ethiopia, rose somewhere around the first or second centuries. and adopted Christianity shortly after its formation. In medieval times much of Eritrea fell under the Medri Bahri Kingdom, with part being part of the Hamasien Republic.