2 Daughter of Phoebus and of Memory,
Phoebus > (The god of music and poetry, who is also sometimes described as the leader of the choir of Muses and is thus called "Musagetes". According to Myth. 4.10, the Muses are the children of Apollo rather than of Jupiter)
3 That do ennoble with immortal name 4 The warlike Worthies, from antiquity,
Worthies > (The nine Worthies comprise (to quote Dryden) "three Jews": Joshua, David, and Judas Maccabeus; "three pagans": Hector, Alexander, and Julius Caesar; and "three Christian knights": Arthur, Charlemagne, and Godfrey of Bouillon. Spenser may also be referring to either or both of the two sets of British worthies: nine privy councillors to William III, including Lord Pembroke; or the Nine Worthies of London (see The Seven Champions of Christendom by Richard Johnson, 1592)) antiquity > ancient times
5 In your great volume of Eternity: 6 Begin, O Clio, and recount from hence 7 My glorious sovereign's goodly ancestry,
goodly > fine, elevated
8 Till, by due degrees and long protension,
protension > extent, duration
9 You have it lastly brought to Her Excellence.
lastly > finally Her Excellence > Her Excellency [Queen Elizabeth]