A genomic study of the lemon indicated it was a hybrid between bitter orange (sour orange) and citron. Lemons entered Europe near southern Italy no later than the second century AD, during the time of Ancient Rome. However, they were not widely cultivated.

How did lemons originate?

They are thought to have originated in north-western India. It is known that lemons were introduced to southern Italy around 200 AD and have been cultivated in Egypt and Iran since 700 AD. Arabs spread lemons throughout the Mediterranean area during the early 2nd century.

Do lemons exist naturally?

Citron is one of the three naturally occurring wild species of citrus (the others are pomelo and mandarin). That means that even lemon is a hybrid — an ancient and naturally occurring hybrid which draws most of its genetic heritage from the citron.