And when it comes to Jewish Diaspora during the Middle Ages, especially in Western Europe:
Some translated excerpts about Jewish economy from the book "The Jewish Civilization" by Feliks Koneczny:
"(...) What about crafts?
We know from previous considerations that each Jewish commune had to include a butcher and a circumciser. Neither the latter nor the former created conditions for the development and expansion of Jewish crafts. This merit goes only to a weaver and a tailor. (...) During the Early Middle Ages tailoring was developing dynamically and rich Islamic caliphates - from Baghdad to Cordova - were supporting that craft even more than Christian states. (...) These three types of crafts - a butcher, a weaver and a tailor - were the earliest ones among the Jewish Diaspora. Just like a weaver implicated a tailor, then later a tailor implicated a capmaker, a cloakmaker and a haberdasher. However, there is no any info about Jewish shoemakers. (...) But something non-kosher could happen while tanning animal skins, which is why Jewish skinners existed much earlier than Jewish shoemakers. Especially early they mastered refined skinning, for example tanning so called Cordovan skins; those artisans were called red skinners or cordovanians. Those were the implications of Judaistic sacredness on the development of Jewish crafts. (...) Those crafts were more advanced among the Muslims than in Christian Europe - which was much poorer. During the Crusades the knights of the cross learned various luxuries and refinements from believiers of the Prophet, and soon after that, "extravagance" became known in Europe. For example silk became the "need" of the richer ones, and only Jewish artisans invited to Europe from the East could satisfy those needs. During the crusades Jewish glassmakers were discovered by Christian knights in the city of Tyre. It is known, that glassmaking was a traditional Ancient craft of that region, which dated back to Phoenician times. However, much more popular than glassmaking were among the Jews such crafts as silkmaking and - related to it - silkdying, which was followed by dying in general. The last Jewish population of Jerusalem during the second half of the 11th century included as many as 200 dyers (colourers). Those types of crafts were adopted from Asian (Middle Eastern) Jews by Byzantine Jews, and from Byzantine Jews to Southern Italy. When in year 1147 a large group of silkweavers was brought with use of force from Constantinople to Palermo, there were many Jews among them. Soon after that silkmaking and dying in Southern Italy became crafts monopolized by local Jews. For a very long time Jews enjoyed exclusive rights for dying in crimson - a colour chosen already in Ancient times for monarchs and royal courts.
Very enlightening is the geographical order, in which Jewish crafts appeared in Europe. Southern Europe, at that time more prosperous and wealthier, already had a large number of Jewish artisans, when in the Frankish Carolingian Empire - so much poorer at that time - there were still almost no Jewish artisans. We can also estimate the density of Jewish population in various regions. For example in some regions in order to transport a Jewish deceased to a nearby cemetery, the corpse had to be in transport during many days. That was the case in Poland, where extremely small number of Jews lived even during the 2nd half of the 13th century and during entire 14th century. The privilege issued by Bolesław the Pious of Kalisz in year 1264 guaranteed freedom of such funeral transports, even in case of very long distance funeral transports. Indeed, permanent Jewish communities existed much earlier in southern regions than in northern ones.
So the professions of European Jews were becoming diversivied. Next to Jewish itinerant merchants (known as the Radhanites), soon stood also Jewish moneylenders and artisans. And what about Jewish farmers? What about landowning? I already described, how at times the right to possess land was granted to Jews, and later cancelled. However, they were not farmers and they did not plan to become ones! Misinterpretation of sources sometimes causes the issue of landowning with farming. This issue has caused many mistakes and this is why sometimes Jews are considered to be grain sowers, while in reality they sometimes used to be wine / grape planters. This is for what they needed land. They already practised that profession in Ancient Palestine. (...) As Zelman Hurwicz wrote - they sometimes were farmers "in some places and in some countries". But Jewish farmers were few. There were a few Jewish farmers in Ancient Babylonia, as well as in Syria and Ancient Gaul. Jews came to Gaul together with Julius Caesar - who was their great debtor and at the same time their protector. In Gaul they often owned peri-urban agricultural land, but did they practise farming? In Arabia during the times of Muhammad some Jews were farmers, others were artisans, but all of them were sedentary people - contrary to nomadic Bedouins. What is interesting, professions of Arabian Jews diversified along the boundaries between clans. While for example a Jewish clan known there as Beru-kainakua did not own any agricultural land, but all of its members were jewellers in Medina, another Jewish clan, Beru-nadhir, was paying taxes amounting to 2,000 "wasks" of wheat and as may as 20,000 "wasks" of dates. The Byzantine Empire vigorously fought against Jewish landowners. That fight started already during the 5th century, but only in Byzantine Syria, because in the Balkan Peninsula at that time we have no info about such events. And when Justinian (527-565) issued a prohibition of owning slaves, running a large farm became impossible.
Western Europe - as we know - was for a long time hesitating whether to prohibit the Jews from owning land, and finally it decided to follow the example of Byzantium - but as we know that formal prohibition remained only on paper. But why would Jews engage themselves in farming grains during period of time when large-scale grain trade still did not really exist in Europe? We can only assume - at the most - that they were sowing some grain for their own use, but that's all, and even that probably only to produce paschal flour for matzos. But vine-growing is another thing. Wine was needed for Jewish rituals every week. They were praying with use of wine (on Friday evenings "kidesz", on Saturdays and during holidays "gabdala"). In the Roman Empire buying a proper, ritually produced wine was not problematic, it was enough to rent some suburban vineyard for that purpose. As we know, expansion of the Roman rule was connected with expansion of vine-growing and olive-growing everywhere. However, after the Roman period and in new countries of the "Diaspora", Jews had to deal with that problem on their own. Thus out of necessity they took care for owning their own vineyards. A famous traveller from the late 12th century - Petachia - described Jewish vineyards at the outskirts of Mosul. But even more the Jews had to take care for wine in Eurpean countries. It is a fact that during the Early Middle Ages nobody prohibited the Jews from owning land. During the Visigothic period Jews owned a lot of land and even long after that they still had a lot of land in the region of Narbonne. In Southern Italy during those centuries we can find a lot of Jewish "possesores", and also in Sicily there were "coloni", that is petty farmers, who worked with their own hands on leasehold land. Weren't those vine-growers?
In the north Christian clergy had to establish their own vineyards, in order to produce sacramental wine. Jews actually needed much more wine for their religious rituals than Christians, because father of each family had to use it. It is known, that Jews owned many vineyards in Austria during the 13th century. In Germany there was a lot of Jewish-owned land near Würzburg, Cologne, Regensburg and other cities. It pays our attention, because from other sources we know, that Jews were prohibited from owning land. But they managed to got round that prohibition by taking land in pledge, together with the right to make use of it. However, in the regions of Speyer and Worms, Jews certainly owned both farmlands, vineyards and gardens - during the 13th century. From that century we also have documentary data which says, that Jews were selling their landed property to German monasteries and chapter houses - which means, that they owned them as their own property before selling them. For example a certain Jew named Samuel sold a large landed estate located near Regensburg to a local monastery. Also in Würzburg a certain Jewish woman named Sara in year 1206 ceded to a local chapter house 6 Morgen of vineyards and two houses located inside the city, at the same time being granted that property for herself and her children as life estate, in exchange for some payments. All of that can be explained if we accept, that those were not rural estates, but urban ones. A typical estate of an urban citizen at that time consisted - apart from a house inside the city - also of some suburban landed property, "belonging to" that house. After all, only many centuries later, together with substantial development of urbanization, burghers totally abandoned agricultural economy. Jews could own countryside / rural landed property in Germany at that time, but they were frequently acquiring suburban estates from burghers together with urban houses. And when even this form of Jewish land ownership started to be persecuted, Jews were forced to sell out that property.
As we can see clergy on many occasions treated Jews leniently and favourably, allowing them to get round various prohibitions, with use of for example feudal law, as in case of that Sara from Würzburg, even though normally Jews had no access to feudal law. Another example of favourable attitude of clergy towards Jews is form the city of Speyer, where Jews wanted to build their houses on land owned by local bishops, which could not be sold to anyone. However, the bishop allowed them to construct their houses there, and granted them a heritable right of making use of them. Is this not the oldest example of law which developed much later under the name of so called Baurecht? (...)
Times changed, but landowning Jews were not becoming farmers themselves. We cannot hear about such cases in sources anywhere. Land moved into Jewish hands as unredeemed pledge, as well as many other "items of all kind", and such an excess of land was rather a trouble for them. What should they do with that land, if Jews don't really need so much land, especially that their need for paschal flour and ritual wine is already satisfied (...)
As for moneylending: (...)
In France by the end of the 12th century it was estimated, that Jewish moneylenders were pulling out from their debtors even up to 5 times the amount of money that had been borrowed. (...) In France and England Jewish moneylending was making the fastest progress. While German Jews were still mostly lending on collateral, French Jews already introduced the institution of a debenture bond. But also clientage of Jewish creditors in France was expanding faster, and during the 12th century it already encompassed not only magnates, but also ordinary knights. Apart from excessive usury, Jews were also accussed of another corrupt practice - namely handling stolen goods. It was commonly considered, that Jewish fotunes could not be considered their private property, because it was believed that their source was illegal, and thus that the authorities had a right to confiscate them. Pope Eugene III, when announcing a crusade in year 1145, arbitrarily wrote off all the debts of its participants. That of course harmed the interests of Jewish creditors. It was also explicitly propagated, that in order to cover the expenses of that crusade, Jewish fortunes could be, or even should be, confiscated from them - as fortunes the source of which was considered illegal - originating from handling stolen goods, excessive usury and frauds. But Bernard of Clairvaus responded to that accusation by declaring, that there are also some Christian usurers, who are even worse than Jewish ones. But of course Bernard did not try to defend them - he simply advocated the confiscation of property for public purposes from all usurers, including Christian ones. Indeed it would be hard to claim that that source of quick multiplication of money, discovered by Jews, did not seduce also some Christians. However, in year 1130 usurers were prohibited from having Christian funerals. And The Third Council of the Lateran in 1179 totally prohibited all Christians from practising the moneylending business. Therefore the Church placed all Christians in an inferior position compared to the Jews; Christians were prohibited from charging any interest at all, while Jews were prohibited from excessive usury, but were granted the right to charge a moderate, limited interest. This is how the moneylending business in Medieval Europe became monopolized by Jews. (...)
Henry III of England cancelled all claims of Jewish creditors. And on the following year in France Jewish landed property was confiscated. Half a century later Jacob I of Aragon in 1228 issued a decree, which said that the maximum annual interest could not be higher than 20%, and the maximum total amount of money that had to be returned could not be higher than 200% of the originally borrowed sum.
(...) Jews were strictly prohibited from owning land in Crusaders' States, but there that prohibition applied not only to Jews - also to Muslims, and even to Orthodox people. (...) Religious dissenters also could not hold offices in those states and could not own slaves in those states.
(...) The closer to the end of the Middle Ages, the more prosperous was Israel in Western Europe, dominating also commodity trading and then proceeding to higher and higher levels of money trading. Great was prosperity of Jews in Western Europe especially during the 14th century (...)
The feature of Jews in Western Europe was that a very large percentage of them were people who were economically independent. This largely contributed to their wealth. It has not been researched yet, whether the Jews were the first people in Europe when it comes to the issue of emancipation of clans / families, but it is very likely. (...) When Israel moved into its "Diaspora", a radical change took place in peoples' mentality, namely that trade became the most important method of struggle for material existence. While farming disappeared almost completely among the Jews, because even Jewish landowners did not deal with trade. This is why movable property became the most important type of property for the Jews, not only in fact, but also in their minds and preferences. A Jewish economic dream was to have more more money, not to have more fields and forests, as was the case with Christians. (...) Christian Europe inherited from the Roman civilization the notion, that the core of property, the most important part of fortune of every person, was always landed property. (...) This is why an excess of Christian population from some place was usually constructing a new town or a new village, rather than migrating to other already existing settlements. But Jews were generally not used to be pioneers, and were not establishing new cities (until the 20th century, when they founded Tel-Aviv, and this still with help of "gentiles"). (...)"
