On the holiday of Passover Jewish law dictates that a person must consume a measure of matza called a kizayis. The word kizayis literally means "like an olive." What exactly the volume of this measure is is a dispute among the medieval and post-medieval authorities. The authorities from Spain and the Mediterranean have smaller volumes that are more in line with the size of the actual olives and the authorities from France and Germany have much larger volumes. There are some who seek to explain that the European authorities erred as a result of not having ever actually seen an olive and therefore they were required to derive the volume from various other sources and ruled stringently. So what I would like to know is, would it have been possible for the authorities in Europe to have actually seen an olive or not? There are those that content that due to olives being a precious commodity and not native to the region that no one would have seen them. But I was under the impression that there are olives that grow in southern France. It wouldn't seem that unreasonable to me to think that rabbis living in the major cities and economic hubs of France would have an opportunity to see an olive. Thanks in advance if anyone can shed any light on this issue.
So what I would like to know is, would it have been possible for the authorities in Europe to have actually seen an olive or not?
Medieval olive pits have been found in archaeological sites as far from the mediterranean as Newcastle in the north of England. This shouldn't surprise us as brined olives are well-suited to storage over time and distance. It would have been costly to import - monks in northern France following the Benedictine reforms in 11th century complained about the expense of olive oil (required by Benedictine rules that were formed in the Mediterranean centuries earlier) and argued that local lard and butter could be used in place. The volume of goods traded between northern Europe and Mediterranean by the late middle ages, including various dried citrus and other southern foods, suggests that whatever the expense may have been the products made it north for urban consumers.
However, why do olives need to travel to the Rabbis? Given the traveling that northern medieval Jews did for talmudic study, particularly in the high middle ages to the olive-rich study centres in the south of France, would they not have seen olives where they grew?
Here is Benjamin of Tudela's 12th century description as quoted by Robert Chazan in his The Jews of Medieval Western Christendom, 1000–1500 (Cambridge, 2006):
From Montpellier it is four parasangs to Lunel, in which there is a congregation of Jews who study the Torah day and night. Here lived Rabbenu Meshullam, the great rabbi since deceased, and his five sons, who are wise, great, and wealthy. [They are:] R. Joseph, R. Isaac, R. Jacob, R. Aaron, and R. Asher the recluse. He [R. Asher] dwells apart from the world and pores over his books day and night, fasting periodically and abstaining entirely from meat. He is a great student of the Talmud. At Lunel, there lives also their brother-in-law R. Moses the head rabbi; R. Samuel the elder; R. Ulsarnu; R. Solomon ha-Cohen; and R. Judah the physician ibn Tibbon the Sephardi. The students who come from distant lands to learn Torah are taught, boarded, lodged, and clothed by the congregation, so long as they attend the house of study. The community includes wise, understanding, and saintly men of great benevolence, who lend a helping hand to all their brethren both far and near.
Given the above, I would argue it very likely that northern medieval Rabbis would have seen an olive at some point in their lives. But we should note here that olives come in a fantastic range of sizes which needs accounting for in any theory.
Although I am not at all familiar with this debate of the measure of kizayis I would say it cannot turn on an idea of whether a population has seen an olive.