This sonnet was attributed to Shakespeare in the 1599 Passionate Pilgrim, and appears as such among the prefatory poems to Henry John Todd's Works of Spenser (1805). Richard Linche's collection of sonnets, entitled "Diella," was published in 1596.
Edmond Malone: "A paper of verses, in which Spenser's 'deep conceit' is praised, has been attributed to Shakspeare, but erroneously; for it was written by Richard Barnefield" Plays and Poems of William Shakespeare (1790; 1821) 2:225n.
Thomas Park: "One of his sonnets thus addresses itself to his friend Master R. L. the author probably of Diello" in Warton, History of English Poetry (1774-81; 1840) 3:328n.
Leigh Hunt ascribes the poem to Shakespeare in his essay "On Commendatory Verses": "We instanced the sonnet in the collection called the Passionate Pilgrim, beginning 'If music and sweet poetry agree,' in which Spenser is praised so highly. It was replied, that minute inquiries considered that collection as apocryphal. This set us upon looking again at the biographers who have criticized it; and we see no reason, for the present, to doubt its authenticity" The Indicator (1819-21; 1845) 2:79.
Leigh Hunt: "I think it probable that he [Shakespeare] wrote the sonnet in which Spenser is eulogized: — 'If music and sweet poetry agree, &c.' but this is doubtful; and Spenser was not one of his dramatic fellows. Did he see too many faults in them all to praise them!!" Imagination and Fancy (1844) 220.
If Musique and sweet Poetrie agree,
As they must needes (the Sister and the Brother)
Then must the Love be great, twixt thee and mee,
Because thou lov'st the one, and I the other.
Dowland to thee is deare; whose heavenly tuch
Upon the Lute, doeth ravish humaine sense:
Spencer to mee; whose deepe Conceit is such,
As passing all Conceit, needs no defence.
Thou lov'st to heare the sweet melodious sound,
That Phoebus Lute (the Queene of Musique) makes:
And I in deepe Delight am chiefly drownd,
When as himselfe to singing he betakes.
One God is God of Both (as Poets faigne)
One Knight loves Both, and Both in thee remaine.