History of refuge in the 3 jewels

When was taking refuge in the 3 jewels of Buddha, Dharma & Sangha started? Was it started by the Buddha in his time or was it after him? When I mean taking refuge, I mean for a lay Buddhist and not for a Bhikku. What is the source of the 3 refuges mantra: Buddhaṃ saraṇaṃ gacchāmi. Dhammaṃ saraṇaṃ gacchāmi. Saṅghaṃ saraṇaṃ gacchāmi.