These events happened from earliest to latest in the following order:
First, the great bath was constructed in the city of Mohenjo-daro aroud the third millenium before Christ
Second, the Rigveda was composed: evidence suggests that it dates from 1500-1200 BC.
Third, The Upanishads were composed: while there is not a consensur regarding when these texts were created, it is believed that it may have occured during the period from VII Century BC to III Century BC.
Finally, The Bhagavad Gita was written: authors believe the Bhagavad Gita to have been written between the V century BCE to the II century BCE.
