Citron
A source of confusion is that "citron" or similar words in French (and other languages), and English are false friends, as they refer to the lemon. Indeed, into the 16th century, the English name "citron" included the lemon and perhaps the lime as well.
Siracusa Lemon
The lemon plant originates in Burma, where it is found growing wild: from there it crossed the Middle East, Mesopotamia, and Palestine, to the Mediterranean, where it found favorable conditions to thrive. The natural habitat of the lemon lies in a strip from the 40° parallel in the North to the 40° parallel in the South: this strip includes California, Uruguay, Argentina, South Africa and the Mediterranean basin, in particular Italy, Spain, Greece and Turkey. In the Fifteenth and Sixteenth centuries, when there was an aristocratic monopoly on citrus growing, the use of lemons was confined to luxury foods.