* Revenge: The most common interpretation is that Lord Randall was murdered by his lover, who poisoned him as an act of revenge. This is supported by the fact that the ballad repeatedly mentions the lady he was with, the poison, and the lack of other potential suspects. The final line, "Make my bed soon, for I'm weary," suggests he knew he was poisoned and that the woman was involved.
* Jealousy: A variation on revenge is that the woman was jealous of another woman, possibly Lord Randall's wife or a rival. She might have poisoned him to eliminate the competition.
* Ambition: It's possible that the woman was motivated by ambition, wanting to inherit Lord Randall's wealth or title. Poisoning him would have been a way to clear the way for her own ascension.
* Political Intrigue: While less likely, there's a possibility that Lord Randall was murdered for political reasons. Perhaps he had enemies who saw his death as a way to gain power or influence.
Ultimately, the ballad leaves the motive open to interpretation, adding to its mystery and intrigue. The lack of clear motive allows audiences to project their own interpretations and speculate about the true nature of the crime.