The goddess is sparsely attested, and what little we know of her is based upon a handful of mentions in the Pyramid Texts.[2][3] These include the following:
utterance PT 211/Pyr. 131, where it is said of the deceased king, "My foster-mother is Iat, and it is she who nourishes me, it is indeed she who bore me" (unknown translator)[3] or "The Milk-Goddess is his attendant. She is the one who will make it possible for him to live: she in fact is the one who bore Unis" (James P. Allen’s translation);[4]
utterance PT 578/Pyr. 1537, where the dead king is told to take on her identity in order to reach the gods in the retinue of the sun: "you should take hold of them, in your identity of the north wind; they will take account of you, in your identity of Anubis; and the gods will not go down against you, in your identity of the Milk-Goddess";[4]
and utterance MAFS PT 1071, which counsels, "Since you are little, you should give your arm to the Sun and sit with your arm to the Milk-Goddess."[4]