Although it was commonly accepted that the sunflower was first domesticated in what is now the Southeastern US, roughly 5000 years ago, there is evidence that it was first domesticated in Mexico around 2600 BC. These crops were found in Tabasco, Mexico at the San Andre's dig site. The earliest known examples in the United States of a fully domesticated sunflower have been found in Tennessee, and date to around 2300 BC. Many indigenous American peoples used the sunflower as the symbol of their solar deity, including the Aztecs and the Otomi of Mexico and the Incas in South America. In 1510 early Spanish explorers encountered the sunflower in the Americas and carried its seeds back to Europe. Of the four plants known to have been domesticated in what is now the eastern continental United States and to have become important agricultural commodities, the sunflower is currently the most economically important. During the 18th century, the use of sunflower oil became very popular in Russia, particularly with members of the Russian Orthodox Church, because sunflower oil was one of the few oils that was allowed during Lent, according to some fasting traditions.