The Ezana stone is an artifact from the ancient Kingdom of Aksum. It is a stone monument which documents the conversion of King Ezana to Christianity and his subjugation of various neighboring peoples, including Meroë.

From AD 330 to 356 King Ezana ruled the ancientAksumite kingdom in the Horn of Africa. Ezana fought against the Nubians and recorded his victories on stone written in Ge'ez (the ancient Eritrean/Ethiopian language), Sabaean (South Arabian) and Greekpraising God for his victories. His carvings in stone provided a trilingual monument in different languages, similar to the Rosetta stone.

Source: http://en.wikipedia.org/wiki/Ezana_Stone