First reference: "Cis n'estoit mie rois de gas, / Ne roi de fierges, ne d'escas, / Ains iert à droit firns rois entirs" (In my eyes he was no pseudo-king, nor king of fierges, but to the end a real king) [Philippe Mousket, 13th c., "Chronique rimé" book II, ll. 23167-9]. In his chronicle Mousket repeatedly used the word fierge as a metaphor for an indispensable power to win a war, also in these lines. The coordination ne roi de fierges, ne d'escas may raise a question mark, it is quite unnecessary to see a reference to draughts.

Second reference: "Thogh ye had lost the ferses twelve / and ye for sorwe mordred yourselve, / You should be dampned in chis cas" [Geoffrey Chaucer, 14th c., "Boke of the duchesse" ll. 722-4]. Once again the word fers occurs in a chess metaphor, a knight bemoans that his wife died during a game of chess: "I lost my ferse, the queen of my heart". The article the in line 722 is difficult to explain, but a reference to draughts in a chess context can never be the first choice. See for more comment Stoep 2005:17-19.

Geoffrey Chaucer