First recorded (as a demo) by Apollonia 6 & Prince (1984).
Hit version by The Bangles (US #2/UK #2/CAN #2/IRE #2/GER #2/AUS #3 1986).
From the wiki: “‘Manic Monday’ was written by Prince, using the pseudonym ‘Christopher’. Originally intended for the group Apollonia 6 in 1984, he recorded it as a duet for Apollonia 6’s self-titled album. However, Prince eventually pulled the song. Two years later, he offered the song to The Bangles.
“It would become The Bangles’ first hit, reaching #2 in the United States and the United Kingdom, as well as in Austria, Canada, Germany and Ireland, and within Top 5 in New Zealand, Norway and Switzerland.”
The Bangles, “Manic Monday” (1986):