Kaṁsa, the son of King Ugrasena, in order to please his sister Devakī on the occasion of her marriage, took charge of the reins of the horses and became the chariot driver. He was surrounded by hundreds of golden chariots.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
उग्रसेनसुतः कंसः स्वसुः प्रियचिकीर्षया । रश्मीन् हयानां जग्राह रौक्मै रथशतैर्वृतः
ugrasenasutaḥ kaṃsaḥ svasuḥ priyacikīrṣayā | raśmīn hayānāṃ jagrāha raukmai rathaśatairvṛtaḥ
SB 10.1.30