Caravaggio: Still Life with Flowers, Fruits, and Vegetables in the Galleria Borghese in Rome, contains a large citron (Citron medica / etrog).
The citron is considered a sacred tree to Jews who know the fruit as the etrog, still used for the celebration of Sukkot, the Feast of the Tabernacles.
The Borghese Gardens Etrog: A few interesting things about Etrogs. The word Etrog is Aramaic, which means "delightful."
The English equivalent word, Citron, is derived from the Greek word "Kedros" -- the same as "Hadar" in Hebrew -- which also means Citrus. Kedros was Latinized as Cedrus, which evolved into Citrus, and then Citron.
In Second Temple times, the Etrog was the only known Citrus fruit, according to Eliezer Goldschmidt, a horticulture professor at Hebrew University. As such, it was the only choice for the Sukkot ritual, as the Talmud states that every Jew should take the fruit of the Hadar tree.
Most Citrus species arrived in the Middle East from China and India, with the Citron first, followed by the Lemon and other Citrus species. The Etrog is still grown in Morocco and Italy. The Italian varieties are mostly Yanaverim types, and there are those who prefer the Italian Yanaver species of Etrog to the typical Israeli Etrog. "Some people believe that the Italian Etrog is the ultimate Etrog," Israeli grower Yaakov Charlap says.
The citron in Calabria was celebrated by poets like Byron and D'Annunzio, but is only saved from extinction, thanks to the Jewish tradition of Sukkot.
A Jewish delegation comes from Israel to Santa Maria del Cedro every year between July and August to choose the best fruit to be used in the holiday for the Jewish community. The selection of the best fruit is a virtual ritual.
The mashgichim, each followed by a peasant carrying a box and a pair of scissors, go to the citron farms at five in the morning. The mashgiach proceeds slowly looking left and right. Then he stops and looks at the base of the tree, right where the trunk comes up from the ground. A smooth trunk means the tree has not been grafted and the fruit can be picked. The mashgiach lies down on the ground to examine better the lower branches between the leaves.
Once the good fruit is found, the mashgiach shows it to the peasant who cuts it off leaving a piece of the stalk. Then the mashgiach analyses the picked citron one more time and if he decides it is worthy he wraps it in oakum and puts it in the box.
The farmer receives the agreed sum for each picked fruit. Then the boxes are sealed and sent to the Lamezia Terme airport with a final destination Tel Aviv
Most adherent to the Diamante variety of Calabria are still the Chabad's who's late Rabbi's were always in support for this traditional variety. Among the other Hasidic sects it is most used by the Satmars.