Hesper and Phosphor are simply the one planet Venus, which according to its position with the sun, becomes the morning or evening star.
"A Key to Lord Tennyson's 'In Memoriam'"
Alfred Gatty
It was this dynasty or people that sent colonies to America: Oviedo says this happened in the time of Hesper 12th king of Spain, about 750 years after the flood, or 1658 years B. C. He deems the settlers Hesperians or Cantabrians.
"The American Nations, Vol. I."
C. S. Rafinesque
Five links, a golden chain, are we, Hesper, the dragon, and sisters three, Bound about the golden tree.
"The Suppressed Poems of Alfred Lord Tennyson"
Alfred Lord Tennyson