In the beginning of Creation, Bhagavān (Bhagavan; the Divine One) Rudra-Śiva (Rudra-Siva) in the form of Nīlalohita (Nilalohita), emerged from the wrath of Brahmā (Brahma). Ilā(Ila) was one of the eleven wives of God Rudra. Actually, Ilā here is the embodiment of the Earth-goddess. The dictionary meaning of Ilā is Pṛthivī (Prithivi; Prithivi; the earth). Elsewhere in Bhāgavatapurāṇa (Bhagavatapurana), we also find the term Ilā, to denote the Earth —
puṣṭikāma ilāṁ yajet.
The commentator clearly says that for gaining puṣti (pusti; physical and vital growth and development) , one needs to worship Ilā or the Earth-goddess, since the Earth-goddess generates the corns and provide food, and proper food is the source of physical strength —
puṣṭirdehavalaṁ tatkāmaḥ ilāṁ pṛthvīṁ yajeta.
This Ilā, an embodiment of the earth-goddess is also conceptualised as the wife of Rudra.
In Vāyupurāṇa(Vayupurana) it is said that in the beginning of Creation, the creators, with the purpose of creating the universe, performed a great yajña (yajna; ritualistic sacrifice), in which they conceptualised Ilā as their wives. The earth, being the fundamental element behind the creation of life, is thus imagined to be the consort of the creator(s).
In this sense, God Viṣṇu (Vishnu), the Ruler and Creator of the universe, is also known as Ilāpati (Ilapati; husband of Ila).