Discussion of exactly what this song “means” has gone on for years. There are those that argue that it’s a “drug song” along the lines of “Luicy In The Sky With Diamonds” (something John Lennon always denied) and “Happiness Is A Warm Gun.” The advocates of this theory claim that Mr. K is a reference to ketamine and Henry the Horse is a reference to heroin.

The truth is that John Lennon spotted a framed Victorian circus poster at an antique shop and bought it during the filming of promotional clips for the “Penny Lane”/”Strawberry Fields” record in January of 1967. The poster was printed in 1843, and announced the appearance of a circus coming to town called Pablo Fanque’s Circus Royal. The poster boasted the “Grandest Night of the Season,” at Town Meadows Rochdale, Lancashire, England. All the characters in the song and the feats they perform come directly from this poster. The phrase “being for the benefit for” was a standard 19th century phrase used in advertising testimonial performances in England. According to Lennon, “I was just going through the motions because we needed a new song for Sgt. Pepper.” As for the horse referenced in the song, the horse is in the poster, but his name is Zanthus. Since the name Zanthus is not very musical, Lennon used the much better sounding name of Henry, making use of alliteration.

Pablo Fanque, Mr. Kite and the Hendersons were real stars in the circus world. Mr. Kite was William Kite, son of circus proprietor James Kite, and an all-round performer. He is believed to have worked in Pablo Fanque’s Circus from 1843 to 1845. Pablo Fanque was a multi-talented performer who became the first black circus proprietor in Britain. His real name was William Darby and he was born in Norwich in 1796. He started calling himself Pablo Fanque in the 1830’s. The Hendersons were wire-walker, equestrian, tramplinist and clown John Henderson and his wife Agnes, the daughter of circus owner Henry Hengler. The Hendersons travelled all over Europe and Russia during the 1840’s and 1850’s. The ’somersets’ which Mr. Henderson performed on ’solid ground’ were somersaults, ‘garters’ were were banners held between two people and a ‘trampoline’ in those days was a wooden springboard rather than stretched canvas.

I have an image of the poster, and I think either John’s son Sean or Yoko is the current owner of the poster.

I hope this helps your understanding of the song.