Paul McCartney's Old English Sheepdog was named Martha. The dog inspired the title of the Beatles song “Martha My Dear,” released on the 1968 double album The Beatles, commonly called the White Album.
McCartney wrote the song alone, although it retained the traditional Lennon–McCartney songwriting credit. Martha was part of McCartney's life during the late 1960s, and her name became one of the most recognizable examples of a personal detail appearing in a Beatles song.
The track itself is not really a straightforward portrait of a dog. Its lyrics and arrangement move through affectionate, playful phrases, while the music combines music-hall character with energetic pop-rock touches. McCartney played piano and several other instruments during the recording.
A common mix-up is confusing Martha with other famous musicians' pets or with names mentioned in Beatles-related songs. The title is the key clue: “Martha My Dear” explicitly connects the name to McCartney's Old English Sheepdog.