Śatapatha Brāhmaṇa ("of a hundred paths") 2.6.1.36

2.6.1.36

sa yemāmavāntaradiśamanu sraktiḥ | tasyāṃ yajamānasya pitre dadātyasāvetatta ityatha yemāmavāntaradiśamanu sraktistasyāṃ yajamānasya pitāmahāya dadātyasāvetatta ityatha yemāmavāntaradiśamanu sraktistasyāṃ yajamānasya prapitāmahāya dadātyasāvetatta ityatha yemāmavāntaradiśamanu sraktistasyāṃ nimṛṣṭe 'tra pitaro mādayadhvaṃ yathābhāgamāvṛṣāyadhvamiti yathābhāgamaśnītetyevaitadāha tadyamevam pitṛbhyo dadāti teno svānpitṝnetasmādyajñānnāntareti

And in the corner (of the altar) opposite this intermediate quarter (viz. the north-west), he then presents (an obsequial cake) to the Sacrificer's father, with the formula, 'N.N., this for thee!' And in the corner opposite this intermediate quarter (the south-west), he presents one to the Sacrificer's grandfather, with 'N.N., this for thee!' And in the corner opposite this intermediate quarter (the southeast), he presents one to the Sacrificer's great-grandfather, with 'N.N., this for thee!' And in the corner opposite this intermediate quarter (the northeast), he cleanses (his hands), with the text (Vâg. S. II, 31), 'Here, O Fathers, regale yourselves! Like bulls come hither, each to his own share!' whereby he means to say, 'Eat ye each his share!' And the reason why he thus presents (food) to the Fathers is that in this way he does not exclude his own fathers from this sacrifice.