Shatapatha Brahmana 11.1.6.5

11.1.6.5

tāni vā !etāni pañcākṣarāṇi tānpañcartūnakuruta ta ime pañcartavaḥ sa evamimāṃlokānjātāntsaṃvatsare prajāpatirabhyudatiṣṭhattasmādu saṃvatsara eva kumāra uttiṣṭhāsati saṃvatsare hi prajāpatirudatiṣṭhat

These (three words consist of), five syllables: he made them to be the five seasons, and thus there are these five seasons. At the end of the (first) year, Pragâpati rose to stand on these worlds thus produced; whence a child tries to stand up at the end of a year, for at the end of a year Pragâpati stood up.