Matsya Purana 261.3

261.3

saptāśvañcaika cakrañca rathaṃ tasya prakalpayet.
mukuṭena vicitreṇa padmagarbhasamaprabham .. 261.2

There should be seven horses and one chakra (wheel) in the chariot of the Sun and a coronet beaming red should be placed on His head—2