The Scythians were horse riding tribes from Iran and the first great nomad conquerors, famous long before the Huns and Mongols. They struck fear into the Greeks and are said to have inspired the myth of the centaur.
They had an empire at one time and had been in parts of Europe and Asia, they were even in China. The Scythians had a tribe called the Xiongnu in China who are said to be the ancestors of the Huns.
The Scythian religion was some form of Zoroastrianism, a religion influenced by the ancient Persian religion. They spoke some form of Iranian language.
Many Scythians also resided in Romania, Ukraine, and Southern Russia.