"A nobleman lived in a mansion, And he courted his own serving maid." He bursts into her bedroom and tries to seduce her. She refuses his advances; she fears pregnancy. He promises to care for her in that case. She refuses again; he marries her
Somewhat reminiscent of the story of Edward IV and Elizabeth Woodville. Edward, who couldn't see a pretty girl without trying to get into bed with her, attempted to seduce the blonde widow of Sir John Grey, but she allegedly said that she was not good enough to be his wife, but too good to be his mistress. So he married her -- to the great detriment of England, sine the marriage arguably added two more phases to the Wars of the Roses (by irritating the Earl of Warwick, which caused the unrest of 1470-1471, and because Edward, when he died in 1483, left only a teenage son with impossibly grasping relatives as his heir, leading to the usurpation or Richard III).
Of course, no one really knows if Elizabeth Woodville said that, and even if she did, it's probably too early to have inspired this song, since Edward and Elizabeth married in 1464. - RBW