[There exists] a letter to Zwingli, dated January 18, 1530, wherein two Swiss in the service of the King of France offer their services to bring about a conference between the representative of the King and of the Zurich allies (viii., 397).
The Landgrave of Hesse took great interest in this mission (cf. his letter of February 1, 1530, viii., 404 sqq.). As these negotiations were delicate, the Landgrave and the Duke of Wurtemberg in writing to Zwingli employed arbitrary signs in their letters to designate certain persons, mostly sovereigns, and also the correspondents themselves. Cf. letter to Zwingli of February 14, 1530 (viii., 411)(SM Jackson).
The Reformation wasn’t just of interest to theologians. It was of interest to politicians as well, for less than theological reasons.