Who were the Aryans?

The Aryans were historically an ancient people from central Asia around the Caspian Sea, and they had a profound influence on the formation of ancient India and Persia/Iran- in fact, the Iranian name for their own country means "land of the Aryans", and goes back over two thousand years. Because the real Aryans lived in a time before writing was commonplace, we don't know a lot about their early history, except that thousands of years ago a group of them invaded India; later a second group invaded Persia (modern Iran). The Vedas, ancient Hindu holy texts, were written in the language of the Aryans, which is now commonly called "Vedic Sanskrit".

However, the problem is that in the late 1800s, certain racist crackpots in France (Arthur de Gobineau) and England (Houston Stewart Chamberlain) began conflating our limited knowledge of the Aryans with Darwinian concepts, and mushed in some occult mumbo jumbo. They came up with the kernel of the idea of a "master race"- that certain people from Europe were ultimately descended from the Aryans, and that these Europeans were inherently better than all other people. It's all nonsense based on inaccurate reading of history.

Adolf Hitler and his Nazi stooges latched onto these "theories" and used them as a basis of their ridiculous racist ideology, claiming that Germanic peoples (Germans, Scandinavians, even some French and English) were "Aryan" and thus better than other peoples. They also decided that Jews and other Semitic peoples were inferior and parasitic, so it was ok for "Aryans" to enslave or kill them. There's no scientific or historical basis behind any of it, and it's utter nonsense. Sadly, a lot of people still believe in it anyway.
As per the answer of our colleague Darth Blinky, the Aryan race were indeed a people originating in central Asia. And, yes indeed the Iranian people once called Persians are part of that genealogy. Iran in Farsi means Aryan.
There were NO Aryans. Hitler made up the "master race" to eliminate those who were "other" than the master race. He used Norse mythology and Teutonic stories to create the history of a master race. The KKK and the white power movement has taken these made up histories to push the white only agenda and hate leading to discrimination and inequality.