"Scarborough Fair" LyricsThe lyrics for "Scarborough Fair" talk about unrequited love. A young man requests impossible tasks from his lover, saying that if she can perform them, he will take her back. In return, she requests impossible things of him, saying she will perform her tasks when he performs his.
It's possible that this tune was derived from a Scottish song called "The Elfin Knight," wherein an elf kidnaps a woman and tells her that, unless she can do these impossible things, he will keep her as his lover.
Parsley, Sage, Rosemary and ThymeThe use of the herbs "parsley, sage, rosemary, and thyme," has been debated and discussed. It's possible that they were just put there as a place holder, as people forgot what the original line was. In traditional folk music, songs grew and evolved over time, as they were passed down through the oral tradition. That's the reason there are so many versions of so many old folk songs, and possibly why these herbs have become such a prominent part of the verse.
However, herbalists will tell you of the many symbolisms and functions of herbs in healing and health maintenance. There's also a possibility that these meanings were intended as the song evolved (parsley to remove bitterness, sage to cleanse, thyme for courage, rosemary for love). There's some speculation that these four herbs were used in a tonic of some sort, to remove curses.