Great piece of games journalism from Duncan Fyfe: the history and legacy of Mastermind. Wide-ranging, great bits of research. Love it.

"The earliest reference to Bulls and Cows is in the work of Dr. Frank King. In 1968, King was studying for a PhD in electrical engineering at Cambridge University and looking for something to implement on the university's Titan computer, which had recently been equipped with Multics, a time-sharing operating system allowing multiple users to access one computer concurrently and remotely.

Thinking a game would be enjoyable, and something more sophisticated than Tic-Tac-Toe even better, King wrote a version of a childhood puzzle. "Good grief, you've implemented Bulls and Cows," he remembers other students saying, though he called it MOO."