I assume this title relates to Robert Devereux, Earl of Essex, who was executed on February 25th 1601, after an unsuccesful rising against Queen Elizabeth on 8th February. A few weeks after Christmas ("Christmas hath made an end"), but in advance of Lent.

Whether the song itself has anything to do with the Earl of Essex is another matter - but I'd imagine that it might have seemed a very appropriate one to sing at the time, and maybe to suggest was sung by the Earl himself while waiting for the chop, which might even have been true, and it's got the right kind of mood for a death cell. And in any case such a suggestion would have been a good way to sell copies of the song.