The basis of the song Shalom Aleichem sung Friday night seems to be the Gemara (Shabbat 119b) about the two angels who accompany a person home on Friday night.
This question discusses why each stanza is repeated 3 times.
My question is: Who authored the song and how did it become so popular that everybody sings it nowadays?
The Avodath Yisroel "Behr" Siddur simply says that it is of "very recent" vintage, author unknown, and that it doesn't exist in any of the early Siddurim.