Spirulina has a history of human consumption in Mexico and in Africa. In Mexico circa 1300 AD the Aztecs harvested Arthrospira from Lake Texcoco and used it to make a sort of dry cake called "tecuitlatl". Very likely the use of Spirulina as food in Chad dates back to the same period, or even earlier, to the Kanem Empire (ninth century AD). It is very interesting that two populations independently discovered the food properties of Spirulina in spite of the differences and the distance. In Chad it is still harvested and processed by hand into cakes known locally as "dihe" for use in a sauce for meat and fish called "la souce". It is an important part of their local economy, allowing the women of the village who harvest and process the dihe a certain amount of independence.