In the Inferno, Minos judges souls at the second circle. Dante places Minos at the entrance to Hell proper, where each newly arrived soul confesses its sins and receives a destination among the lower circles.
In Canto V, Minos is portrayed as a terrifying, serpentine judge. He wraps his tail around his body a number of times, with the number indicating the circle where the soul must suffer. The second circle is reserved for the lustful, who are swept endlessly through a dark, violent storm.
Dante adapted Minos from classical mythology. In Greek tradition, Minos was the legendary king of Crete and, after death, became a judge of the underworld. Dante's version also incorporates traits associated with Rhadamanthus, another mythological judge of the dead.
A common mix-up is to name Rhadamanthus, Aeacus, or Pluto. All are connected with the classical underworld, but Dante specifically assigns the judging role at Hell's entrance to Minos.