According to the Online Etymology Dictionary, the word first appeared in print in 1429. (Of course, promotion
may have been around in conversation from an earlier date, but nobody can prove it existed without a written record.)
The original use of the word translated to "advancement," from the Old French of the same spelling. Fast forward to 1925, when promotion took on new meaning as wordsmiths began applying it to "advertising" and "publicity."
Way back in 1387, the word promote cropped up to describe movement to a "higher grade or office." A person who promotes — a "promoter" — was mentioned in writing as early as 1450. The more modern association of a promoter with the sports or entertainment industries didn't arrive until 1936.
Nowadays, the noun promotion can refer to a job advancement, ballyhoo about a new movie, progress of an idea or enterprise, or growth of a tumor (in medical terms). Promotion is also a term found in the game of chess and among sports teams that move up to higher leagues. And, if you happen to be pursuing a doctorate degree in Germany, you're actually seeking a Promotion (equivalent to a PhD)!