The name Dario ranked 844th in popularity for males of all ages in a sample of 2000-2003 Social Security Administration statistics and 976th in popularity for males of all ages in a sample of the 1990 US Census.
This was the Greek version of the name of a number of Persian kings. One of these was defeated by the Greeks at the battle of Marathon in 490 B.C. Another, his great-grandson, lost his empire to Alexander the Great 160 years later.
The Old Persian origin of this name is darayava(h)us and means ''he who upholds the good.''