Immigration is of course an old issue. The history of mankind is a story of people moving from one area to another. And often, the people living in an area are not too happy to see newcomers arrive. The was the case in the second century Roman Empire.
Numerous German tribes wanted to live in the Roman Empire. However, for the most part, they did not desire to live in the Roman Empire as Roman citizens, speaking Greek and Latin, paying taxes, and serving in Roman legions.
The German tribes wanted to live in areas of the Roman Empire they conquered and peaceful coexistence with the Romans was not high on their list nor was the process of Romanization. Marcus Aurelius, the stoic philosopher and last of the Five Good Emperors, was the first who had to deal with it in the second century.
The Marcomanni and Quadi crossed the Danube in 169, marched across several provinces, and invaded Italy. This was a major shock to the Romans who had not seen Italy invaded by a foreign power for several centuries. Marcus Aurelius would spend most of the last eleven years of his reign fighting the German Wars.
He died (possibly of the plague) while fighting on the German frontier in 180. Although he was successful in stopping the invasion, his successors would prove less capable and these German tribes would eventually help to bring down the Western Roman Empire.
One idea that Marcus Aurelius tried in addition to warfare was to allow a few of the less objectionable tribes to settle peacefully in the Roman Empire. The Empire had been devastated by the plague when Roman legions brought it back after the Parthian War.
This created a huge shortage of men being available to fight in the Roman military. Marcus was hoping that these tribes would provide men for fighting and for growing food. And, he hoped they would eventually Romanize... Michael Lorenzen in Marcus Aurelius: The Philosopher-Emperor of Rome wrote, "As such, systems theory is one way to understand why Marcus Aurelius agreed to allow some German tribes to settle in the Roman Empire in peace. Some historians criticize this move as it lead to the later 'barbarization' of the Roman Empire.
However, due to plague, the Roman Empire had become severely depopulated. There were few to grow crops and to provide soldiers for future legions. " Birley in Marcus Aurelius: A Biography (2000) wrote, "It could even be argued that depopulation of the countryside, especially Italy, had been beginning before the plague, to an alarming extent.
Beside this, if the settlers were from peoples which Marcus intended to incorporate within the empire, the criticism has less points in any case. They were to be romanized sooner or later, by one means or another" (p. 170). It is hard to judge whether Marcus Aurelius's decision to let in a few tribes while fighting the rest led to the barbarization of the Roman Empire.
The Romans had no choice but to try and coexist with the German tribes. The Romans did not always have the strength to fight back. Maybe it was a bad idea. But then again, Marcus really did not have many good options. And several thousands years later, the whole issue of immigration and assimilation remain newsworthy not only in what was the Roman Empire but around the entire globe.
And it will continue to be an issue for the next several thousand years too I bet.