SB 11.24.11
so ’srjat tapasa yukto
rajasa mad-anugrahat
lokan sa-palan visvatma
bhur bhuvah svar iti tridha
Translation:
Lord Brahma, the soul of the universe, being endowed with the mode of passion, performed great austerities by My mercy and thus created the three planetary divisions, called Bhur, Bhuvar and Svar, along with their presiding deities.