Who is Van Morrison refering to in the song The days before rock and roll as Justin gentler than a man?

In "The Days Before Rock and Roll," Van Morrison refers to the legendary musician and cultural figure, presumably referring to a more innocent and gentle time in music and society. The phrase "Justin gentler than a man" evokes a sense of nostalgia for an era characterized by authenticity and emotional depth, contrasting sharply with the more commercial and aggressive nature of modern rock and roll. This reference highlights Morrison's longing for a simpler, more genuine musical experience.