Tibullus describes Apollo's love to the king as servitium amoris (slavery of love) and asserts that Apollo became his servant not by force but by choice.
tˈɪbʊləs dᵻskɹˈaɪbz ɐpˈɑːloʊz lˈʌv tə ðə kˈɪŋ æz sɜːvˈɪɾiəm ˈæmoːɹˌɪs slˈeɪvɚɹi ʌv lˈʌv ænd ɐsˈɜːts ðæt ɐpˈɑːloʊ bɪkˌeɪm hɪz sˈɜːvənt nˌɑːt baɪ fˈoːɹs bˌʌt baɪ tʃˈɔɪs.