Puru was the son of Yayāti (Yayati). Raudrāśva(Raudrasva) was the third son of this Puru. Ten powerful sons were born of the womb of the Apsarā (Apsara; Celestial courtesan)Miśrakeśī (Misrakesi), and sired by Puru. Ṛceyu (Richeyu)was the eldest and the worthiest of these ten sons. Since Ṛceyu was so powerful , it was impossible to overpower or assault (dharṣaṇa) him in war. So, his alternative name is Anādhṛṣṭi (Anadhrishti) (dhṛṣ + anaṭ = dharṣaṇa; dhṛṣ+ktin = dhṛṣṭi; the meaning is the same). Matināra (Matinara) was the son of Anādhṛṣṭi or Ṛceyu. (see Anādhṛṣṭi) .

Another name of Ṛceyu is Anvagbhānu (Anwagbhanu) — that is, due to his brilliant energy, even Bhānu (Bhanu) or the Sun seemed to follow him. This name became so famous that while naming the sons of Raudrāśva, it is said that Raudrāśva and Mirakeśī gave birth to ten sons — namely, Anvagbhānu and others, like Ṛceyu (Richeyu), Kakṣeyu (Kaksheyu), Kṛkaṇeyu (Krikaneyu)and so on —

anvagbhānuprvṛtayo miśrakeśyāṁ manaśvinaḥ.

In his Bhāratakaumudī-tīkā (Bharatakaumudi-tika; the commentary of Bharatakaumudi with annotations), Haridāsa Siddhāntavāgiśa (Haridas Siddhantabagish) has said that the eldest son of Raudrāśva(Raudraswa) had three names — Anvagbhānu, Ṛceyu and Anādhṛṣṭi —

evañca Raudrāśva-jyeṣṭhaputrasyaiva anvagbhānu

ṛceyuḥ anādhṛṣṭiśceti nāmatrayaṁ mantavyam.

(See Anādhṛṣṭi and Anvagbhānu)

In Purāṇa (Purana; Mythological Scripture), rājarṣi (rajarshi; a king with the attributes of a sage-seer)  Ṛceyu(Richeyu)  is also known as Ṛteyu or Ṛceṣu (Richeshu). According to the description of Purāṇa, the name of his son was Rantināra (Rantinara)or Rantibhāra (Rantibhara).