Why, Petruchio is coming in a new hat and an old jerkin, a pair of old breeches thrice turned, a pair of boots that have been candle-cases, one buckled, another laced, an old rusty sword ta’en out of the town-armory, with a broken hilt, and chapeless; with two broken points: his horse hipped with an old mothy saddle and stirrups of no kindred; besides, possessed with the glanders and like to mose in the chine; troubled with the lampass, infected with the fashions, full of wingdalls, sped with spavins, rayed with yellows, past cure of the fives, stark spoiled with the staggers, begnawn with the bots, swayed in the back and shoulder-shotten; near-legged before and with, a half-chequed bit and a head-stall of sheeps leather which, being restrained to keep him from stumbling, hath been often burst and now repaired with knots; one girth six time pieced and a woman’s crupper of velure, which hath two letters for her name fairly set down in studs, and here and there pieced with packthread
In these lines, Biondello is describing the ridiculous display that Petruchio puts on as he goes through town to wed Katherine. Everything that he is saying and doing seems extremely silly and overdone, from his clothes (which are old, mismatched, and out of fashion) to his horse (which is old and swollen with disease). Petruchio is doing this to establish his dominance over Katherine, and to humiliate her into submission. By parading through town dressed in an absurd outfit and showing up late to the wedding, he is solidifying a fact that had been only implied earlier: Katherine has no choice but to marry him, no matter how awful he is to her. Baptista has promised him the wedding, and he doesn’t believe that anyone else would want to marry her. It also works to dehumanize Katherine. By refusing to give her a proper wedding (which, at that point, was the only was a woman could achieve success), Petruchio strips her of her womanhood, her identity, and (to an extent) her humanity. He implies that her forward and aggressive nature makes her more of a wild animal and less of a woman. This is his first act in “taming” her, in which Petruchio fully understands the power that he holds above her head.