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.
Greek citron
Historically speaking, the citron is considered by numerous writers, to be introduced to Europe by the troops of Alexander. It was also described by Theophrastus, who succeeded Aristotle as the curator of the Botanical garden in Athens.