As the son of the Earl of Leicester's sister, the 15-year-old Philip Sidney was being considered in 1569 by William Cecil as a prospective husband for Cecil's daughter Anne, then 12 years old (Ogburn and Ogburn 37). Negotiations fell through, probably because Cecil decided to aim higher, which worked when he shoved Anne onto his ward Edward de Vere, 17th Earl of Oxford.
He ended up marrying the daughter of Walsingham, Elizabeth's spymaster after Burghley delegated the chore. Sidney admitted he wanted to be first a soldier, and he died from a leg wound in the Low Countries. Despite his father-in-law's financial difficulties, Sidney received a funeralaganza as a national hero, nearly a martyr for Protestantism, but this took place four months after his death when the need arose to create an enormous diversion from the execution of Mary, Queen of Scots. Flippy's funeral was scheduled the following week. Coincidenza? (Ogburn and Ogburn 765).
Sidney is on record with a written challenge in 1578 to a Molyneux: "You have played the very knave with me, and so I will make you know if I have good proof of it. But that for so much as is past. For that is to come ... I will thrust my dagger into you, for I speak in earnest." The Norton Anthology (975) fails to complete this ferocious epistle: "In the meantime farewell" (qtd. in Ogburn and Ogburn 278).
Astrophil and Stella adheres to Petrarchan convention in most respects, first including the adoption of classical sounding names, Stella meaning star and Astrophil star-lover. The sonnets were devoted to Penelope Devereux, who married Lord Rich in 1581. #37 laboriously and ill-advisedly tries to pun on "Rich."
#2 "Not at first sight." Oxford takes swipes at this Sidney perspective in As You Like It with the "Dead poet" reference (Ogburn and Ogburn 466) and in Much Ado About Nothing with Claudio's "I look'd upon her with a soldier's eye" passage (I.i.292ff), anatomizing the methodical process of supposed love (Ogburn and Ogburn 493).
#9 ("She's a brick house.")
#18 (financial conceit)
#34 (a dialogue)
#39 (an insomnia poem)
#45 (Paula Payne says it's one of the worst) "I am not I: pity the tale of me."
#49 (horse conceit)
Here's more about Philip Sidney from the Shakespeare/Oxford perspective. "Philip Sidney (who was not, by the way, knighted until three years before his death) was beyond all doubt an estimable young man, courtly and brave.... As a poet, however, he was merely facile: imitative (to put it charitably) at best, sentimental and even silly at worst..." (Ogburn and Ogburn 184). He may get away with much of the affectation since later ages consider this to be refinement, but he clearly embraces the mechanical rather than the spontaneous.
Indications from Love's Labor's Lost are that Sidney's only real skill was his ability to "peck up wit as pigeons pease" (V.ii.316f), and one can trace his plagiarizings from Oxford and Spenser (Ogburn and Ogburn 185). In Twelfth Night, Sir Andrew "pecks up wit" (III.i.87ff) (Ogburn and Ogburn 277). And the pathetic challenge from Sir Andrew, plus its written form, surely come from Sidney's momentum towards challenging Oxford to a duel after the infamous tennis-court incident in 1579 (Ogburn and Ogburn 273, 275). Sir Andrew and Slender from The Merry Wives of Windsor use the same expression -- Sir Andrew "a-hungry" (II.iii.128) and Slender "a-hungry" (I.i.264) -- that seems to have come from Sidney (Ogburn and Ogburn 275). Also in The Merry Wives, Falstaff says to Mrs. Ford, "Have I caught my heavenly jewel?" (III.iii.41), a quotation from Astrophil and Stella. Slender is related to Robert Shallow, so Robert Dudley, Earl of Leicester (Ogburn and Ogburn 726). Slender uses the phrase "boy yet" (I.i.264f) (Ogburn and Ogburn 745). Boyet in Loves' Labor's Lost seems to be Sidney (Ogburn and Ogburn 199, 726, 745), and references suggest either that Sidney was good at carving (V.ii.318, IV.i.55) or these are intended to put us in mind of Chaucer's Squire in The Canterbury Tales who is similarly out of touch with love and enamored with convention.
In Much Ado About Nothing Oxford represents again his own regretted distrust of his wife. "But the namby-pamby side of Claudio, willing to give up his betrothed without question and with small show of feeling, is Philip Sidney, who seems to have been emotionally immature, if not insipid" (Ogburn and Ogburn 493).
Ned Poins in Henry IV, Part One is a near anagram for P. Sidnei -- as Sidney signed himself (Ogburn and Ogburn 704). Perhaps he disappears from the adventures because of the dating of portions of these plays surrounding Sidney's death.
Ogburn, Dorothy and Charlton Ogburn. This Star of England. Westport, CT: Greenwood Press, Pub., 1952.
Sidney, Philip. Astrophil and Stella. The Norton Anthology of English Literature, Volume 1. 8th ed. NY: W.W. Norton & Co., 2006. 975-992.