The Transvectio Equitum was a parade of the Equites held on July 15 in honor of Castor and Pollux. It commemorated the Battle of Lake Regillus (496 BC) in which the Dioscuri aided the Romans against the Latin League. It lasted for several years after its inception in 304 BC and then revived under Augustus.

The Equestrians, clad in togae trabeae and mounted on their horses, filed past the Censors in procession on their way from the Temple of Mars on the Appian Way --about 2 kilometers outside the Porta Capena-- to the Capitolium. They halted along the way to sacrifice in the Forum at the Temple of Castor and Pollux.