Speak/talk of the devil

Said of a person who when spoken about, suddenly appears by coincidence and dates in this sense from the early 20th century, but it has a long history. The original expression was ‘talk of the devil and he doth appear’, which dates from medieval times where it appears in several different formats in Latin and Old English texts. It was a medieval superstition that was taken very seriously. During subsequent centuries, the overall meaning was somewhat tempered to ‘talk about evil and evil or bad things will happen’. It was not until the 19th century that it started to migrate from such sinister, negative meanings to become the innocent expression that it is today.