“limbs with travel tir'd”
'Travel' here carries its older sense of travail — laborious exertion and hardship — as well as the modern sense of journeying. The two meanings blend deliberately: the poet is worn out both from the physical effort of the road and from the toil that accompanies it. The spelling 'travel' and 'travail' were interchangeable in Elizabethan English.
“thoughts—from far where I abide— / Intend a zealous pilgrimage to thee”
A pilgrimage is a devotional journey to a sacred shrine. By calling his mind's nightly journey toward the beloved a 'zealous pilgrimage,' the poet casts the absent person as a holy destination and his longing as an act of religious devotion. 'Zealous' intensifies this: zeal in Elizabethan usage described fervent religious ardor.
historical Petrarch and the Petrarchan loverhistorical Pilgrims, palmers, and holy shrines“keep my drooping eyelids open wide, / Looking on darkness which the blind do see”
The paradox 'darkness which the blind do see' means: the poet lies awake in the dark staring at nothing — the same nothing the sightless always face. His open eyes perceive only what a blind person perceives: blackness. The line uses paradox to collapse the difference between open and shut, seeing and blind, making the night's blankness total.
historical The sonnet form“my soul's imaginary sight / Presents thy shadow to my sightless view”
'Shadow' does not mean a patch of darkness here; it means a phantom image — a mental projection of the beloved's form, not the beloved in person. 'Sightless' means unable to see (the eyes are shut or useless in darkness), but also carries the sense of invisible: the view is both blind and seeing nothing. Together they define what the mind produces when the body fails: an image that is real to the imagination but has no physical existence.
“like a jewel (hung in ghastly night, / Makes black night beauteous”
This is the sonnet's central image (its conceit): the beloved's imagined form in the mind is like a jewel hung in the terrifying dark of night — a single brilliant object that transforms the blackness around it. 'Ghastly' means horrible, deathly, spectral (not merely 'ghostly' in the mild modern sense), so the night is not just dark but frightening. The jewel's radiance makes the surrounding darkness beautiful rather than threatening.
historical The 1609 Quarto and 'Mr. W.H.'