This is a monophonic piece (i.e. only one part, no harmonies) by the 14th-century composer Guillaume de Machaut. Some people like doing it very quickly; I like it slow and slinky. For fun (certainly not for an authentic 14thC sound) we did a jazzy version with Katherina, William and Anna singing, Gregory on trumpet, and Ludwig on drums.
There are many recordings on CD, and many more on YouTube.
A seventh: B-flat to C at the pitch above.