Sidney's sonnet begins with a puzzle that sounds almost like a complaint. Why would Nature, making her "chief work," Stella's eyes, wrap such bright beams in black? The speaker doesn't puzzle for long. Over twelve lines he tries out one explanation after another, each more flattering than the last, and the final couplet gives an answer that is both a compliment and a small, dark joke.
The three quatrains work as three hypotheses, all posed as questions. The first imagines Nature as a painter, "wise" enough to know that a rich brightness comes from "shades and light" mixed together, as a dark background makes a highlight glow. The second explanation is more practical. Black may be the colour that best helps the eye to "knit and strength our sight," while also acting as a veil. Without it, the "brave gleams" would be "sun-like" and "more dazzle than delight." That phrase is neat. The two verbs start alike but mean nearly opposite things, and the line suggests that Stella's eyes are so brilliant they would be hard to bear unshielded. The third explanation is the boldest: black only "seems Beauty's contrary," and Nature chose it to show her "miraculous power" by making "all beauties flow" from the very colour that should forbid them. Notice the word "seems." The speaker admits that black looks like a flaw, then gently takes the idea apart.
The rhyme scheme (abab abab cdcd ee) helps the argument along. The first eight lines use only two rhyme sounds, so the octave circles back on itself, as though the speaker keeps returning to the same dazzling fact. The rhymes also gather meaning. "Bright," "light," "sight" and "delight" all belong to seeing and pleasure, while "wise," "devise" and "disguise" belong to craft and concealment. In the third quatrain the sounds change as the idea of miracle arrives, and the couplet closes with "weed" and "bleed," a pairing that feels like a door shutting. The iambic pentameter is steady and unhurried, which suits a speaker reasoning his way through a case. The line "she minding Love shoud be / Placed ever there" runs over the line break, and the enjambment adds to the sense of Love settled permanently in that spot.
A pattern of clothing runs underneath all this. The beams are "wrapp'd" in black, then given a "veil" and a "disguise," and finally Love himself is handed a "mourning weed," an old word for a garment, as in a widow's weeds. The image moves from the colour of the eyes to the costume of Cupid, who lives in them. The couplet explains why he wears black. He is honoring "all their deaths, who for her bleed." Here the speaker uses the familiar love-poet's pretence that lovers wound and kill each other. The bleeding suitors are casualties of Stella's gaze, and her black eyes serve as the funeral dress for their loss. The earlier idea that black is "Beauty's contrary" reaches its sharpest turn here. Beauty and death are close neighbours, so black suits her after all.
What makes the poem worth reading is the way it handles its own cleverness. A feature that might be questioned becomes the proof of Stella's power, and the argument is built to hold back the answer until the couplet, so that the questions feel like a game the reader gets to play along with. The first words of the couplet then declare that every explanation was right at once, so the speaker is not choosing one reason but piling them up. That generosity is part of the joke. Even a simple colour needs three theories and a funeral to do justice to her.
The number in the title suggests a place in a longer sequence about Stella, yet the sonnet stands alone as a lesson in how a fixed form can be used for debate. It also shows how praise can be made out of paradox, with darkness that glows, a veil that reveals, and mourning worn by Love himself.