The Odes by John Keats

‘Phoebe’s sapphire-region’d star’ – Phoebe is a goddess and her ‘star’ is the moon, which is called ‘sapphire-region’d’ because it is surrounded by the dark blue of the sky just after sunset and before sunrise.

‘Vesper, amorous glow-worm’ – Vesper is the Evening Star, which is actually the planet Venus, hence ‘amorous.’ It is a ‘glow-worm,’ perhaps, because Venus is generally seen fairly close to the horizon, and could at a stretch be a fire-fly. Perhaps Keats also knew that glow-worms use their light to attract a mate.

‘When holy were the haunted forest boughs’ – Keats is nostalgic for the days when spirits were believed to fill the natural world. The Romantic movement, of course, rediscovered the divinity of nature.

‘I see, and sing, by my own eyes inspired’ – not literal. Keats means the inner ‘eyes’ of his imaginative mind.

‘a fane’ – It is to be expected that Keats would choose this slightly obscure, archaic word (meaning ‘temple’), but there is also a play on the verb ‘to feign.’ Psyche’s temple is ‘feigned,’ imagined, unreal.

‘In some untrodden region of my mind’ – In other words, Keats is engaging in creative work that is different to anything else he has tried.

‘pleasant pain’ – oxymoron referring to artistic creation. It involves painstaking work, but brings deep pleasure and satisfaction.

‘the midst of this wide quietness’ – Notice how the two examples of i assonance (one on the short i, one on the long) create a sense of expansiveness appropriate to the meaning.

‘A bright torch’ – a signal for a rendezvous, like a candle in a window.