Catur yuga
From Hindupedia, the Hindu Encyclopedia
Rāmāyaṇa where ideology and arts meet narrative and historical context by Prof. Nalini Rao
Rāmāyaṇa tradition in northeast Bhārat by Virag Pachpore
Catur Yuga refers to the time encompassed by the passing of 4 yugas
It covers approximately 4.32 billion solar years.