Śatapatha Brāhmaṇa ("of a hundred paths") 2.4.3.5

2.4.3.5

tāvindrāgnī udajayatām | tasmādaindrāgnau dvādaśakapālaḥ puroḍāśo bhavatīndrāgnī hyasya bhāgadheyamudajayatāṃ tau yatrendrāgnī ujjigīvāṃsau tasthatustadviśve devā anvājagmuḥ

Indra and Agni won, and hence that Indra-Agni cake on twelve potsherds; Indra and Agni having won a share in it. And where Indra and Agni were standing when they had won, thither all the gods followed them.