The history of the Roman Empire is a fascinating study in the skillful interplay of the two faces of the struggle between states which are known as war and diplomacy. And the Romans, as we see in reviewing the growth of this empire, were masters of these two aspects of statecraft. The Romans intruded in the affairs of the Jewish People at the time of the Maccabean struggle against the rulers of the Seleucid Empire. The account in the Book of First Maccabees relates the events which led to the struggle of the Jews who were devoted to traditional Judaism against those who were willing to betray their people by joining with the Pagans and compromising the faith of the Torah.
When the dispute between the two sides descended into violence, the sons of Mattityahu Hashmonai Ha-Kohen of Modin, led by Judah, known as Maccabee, organized a resistance force of devoted Jews who fought against the armies of Antiochus Epiphanes, at that time the ruler of the strongest military force in the region. By virtue of the skill of Judah Maccabee and his devoted allies, among whom was a group of pious Jews known as Hasidim, the Jews won some very significant victories.
These events attracted the attention of the Romans. They were delighted that their only significant rival in international affairs was having trouble with one of his subject nationalities. Seizing the opportunity of the moment, the Roman Senate sent ambassadors to Judah Maccabee offering their friendship and assistance. The result was that Judah sent two ambassadors to Rome who were hailed by the Senate and, as a result of this meeting a Mutual Defense Treaty was drawn up binding the Romans and the Jews in an alliance which threatened the Seleucid Empire.
Thus was a Jewish embassy established in Rome. With their staff, secretariat, and other essential personnel, the first Jewish community of which we have a written record was established in Europe in 161 B.C.E.
Incidentally, the struggle fought by the Hasmoneans and their allies, the Hasidim against the Hellenizing priesthood in Jerusalem , was the forerunner of the great conflict that developed within the next half century between the Sadducees and the Pharisees.
Gradually, a migration of Jews to Rome and Italy began shortly after this time. It is interesting to note that the first generation of Jewish immigrants to Rome came from the large Greek-speaking cities of the Hellenistic region. This is apparent from the inscriptions on the gravestones that have been found in the Jewish catacombs in Rome, all of which –with few exceptions– are in Greek.
As Rome extended its control over other parts of Europe beyond the Alps and the Pyrenees, we find that Jews moved together with the Roman conquests. Evidently merchants were encouraged to follow in the train of the armies to provide the soldiers with goods that they could not get in the forests and river valleys of Gallia and Germania. In the course of time every Roman military camp, called Colonia in Latin, attracted a civilian population and cities began to rise in what were military encampments. The great German city of Köln on The Rhine, called Cologne in French and English, was originally a Roman military encampment called Colonia Agrippinensis. A Jewish community was well established in Cologne sometime before 50 B.C.E.
Well before the beginning of the Common Era there were Jewish communities established in all parts of the Roman Empire. This included the Greek cities in the eastern Mediterranean and Aegean areas, the Greek and Roman cities in all of North Africa, the Iberian Peninsula, including Spain and Lusitania (Portugal), as well as all of western Europe, including Britain. Incidentally, there is evidence that the Jews in Spain had been there for centuries before the Roman conquest. The Jewish name of Spain is Sefarad. The Jews are the only people who refer to Spain as Sefarad; everyone else calls the land Espania. And Sefarad is a very ancient designation for a part of the country which has been preserved only by its Jewish inhabitants from remote antiquity.
[Sources: Strabo, Cicero, Josephus, King Agrippa.]