The origin of the lemon is a mystery, though it is thought that lemons first grew in Assam (a region in Northeast India), northern Burma, and China. A study of the genetic origin of the lemon reported that it is a hybrid between sour orange and citron.
Lemons were known to the Jews of Jerusalem, who, according to Josephus, pelted an errant high priest with them during a festival in the 90s BC, although Jewish tradition maintains that this was done with citrons, not lemons. They entered Europe near southern Italy no later than the 1st century AD, during the time of Ancient Rome.
However, they were not widely cultivated. They were later introduced to Persia and then to Iraq and Egypt around 700 AD. The lemon was first recorded in literature in a 10th-century Arabic treatise on farming and was also used as an ornamental plant in early Islamic gardens. It was distributed widely throughout the Arab world and the Mediterranean region between 1000 and 1150 AD.
The first substantial cultivation of lemons in Europe began in Genoa in the middle of the 15th century. The lemon was later introduced to the Americas in 1493 when Christopher Columbus brought lemon seeds to Hispaniola on his voyages. Spanish conquest throughout the New World helped spread lemon seeds. It was mainly used as an ornamental plant and for medicine. In the 19th century, lemons were increasingly planted in Florida and California.
The juice of the lemon may be used for cleaning. A halved lemon dipped in salt or baking powder is used to brighten copper cookware. The acid dissolves the tarnish and the abrasives assist the cleaning. As a sanitary kitchen deodorizer, the juice can deodorize, remove grease, bleach stains and disinfect; when mixed with baking soda, it removes stains from plastic food storage containers.