From Count Jehan:

I hope to send fuller comments later, but I wanted to be sure to submit this comment as it pertains to a matter in my particular area of professional expertise. (My Ph.D. dissertation was on the reign of Richard II of England, when this palace existed). Although this palace belonged to John, Duke of Lancaster, known as John of Gaunt, it was never referred to in any period source I have read (and I have read a great many) as "Gaunt's Savoy." The palace was simply known as "the Savoy" (or "Le Savoy" in Anglo-Norman.) Nor is it called "Gaunt's Savoy" in most modern scholarship. For example, Nigel Saul's Richard II (New Haven, Yale UP 1997:58-59) (the new but already standard biography) says "in the course of the Revolt" (of 1381) "his" (Lancaster's) "palace of the Savoy in the western suburbs of London was burned down." The lady could take the name Serena of Gaunt (the ME form of Ghent) or Serena of Savoy (a duchy on the French/Italian border) but *not* Gaunt's Savoy.