tasya—of Lord Vamanadeva; upaniyamanasya—at the time of His being offered the sacred thread ceremony; savitrim—the Gayatri mantra; savita—the sun-god; abravit—chanted; brhaspatih—Brhaspati, the guru of the demigods; brahma-sutram—the sacred thread; mekhalam—the belt of straw; kasyapah—Kasyapa Muni; adadat—offered.