“The sweetest morsel of the night moreover was, that the musicians began pegging and fagging away—at an overture—never did you see faces more in earnest, three times did they play it over, dropping all kinds of corrections and still did not the curtain go up.”
Keats is no seraph. He has a healthy, mocking sense of humor. He makes fun of the musicians. I wasn’t sure about “pegging and fagging away.” The OED cites Keats’ use of pegging and defines his sense of peg as “to toil laboriously over a long period; to work or go at persistently.” Fag as an intransitive verb is virtually a synonym, defined as “to work hard (at something, esp. something tedious); to labour, toil.” We’ve all seen dutiful, under-gifted musicians, especially young ones, sawing away at their instruments. When Junior is pushed into performing by Mommy and Daddy, the result is simultaneously excruciating and laughable.
Keats is suffused with Shakespeare. At the start of the passage quoted above, he silently alludes to Falstaff in Henry IV, Part II: “Now comes in the sweetest morsel of the night, and we must hence, and leave it unpick’d.” Prince Hal is returning to court and has just departed. He wishes Falstaff a good night. When Falstaff next sees Hal, the prince will be king and will reject his old friend. Also, with dinner over, “sweetest morsel” implies the evening’s next pleasure, sex. Keats, of course, would have known all of this. The letter to his brothers also includes a sonnet, “On Sitting Down to Read King Lear Once Again.” It’s a middling poem by Keats’ standards but includes these lines: “. . . once more humbly assay / The bitter-sweet of this Shakespearian fruit. / Chief Poet!” He also wrote the sonnet in his facsimile edition of the First Folio.
Later that year, his brother George would sail to the United States and settle in Kentucky, where he remained for the rest of his life, and Tom would die of tuberculosis at age nineteen. The same disease would kill the poet three years later.