Teff was one of the plants and grains domesticated by ancient Ethiopian and Eritrean nomadic tribes and farmers. The earliest known variety was around 5000 BC, and this grain has been found in Egyptian pyramids where it was once considered as a last meal for the Pharaohs!
While the grass and grain are well known in East Africa, they haven’t been as popular in the rest of the world, partly due to difficulties in growing them in a climate different from that of the East African grassy highlands. But recent advances in agriculture have now enabled the cultivation of the grain in other countries, including Spain, which accounts for a significant source of the world’s supply of teff.
Source: One Curious Ingredient: Learning About Teff | Food Bloggers of Canada