“Charles is a young prince, Spain is a grasping, restless, proud, dissolute people. Why should the Germans so inconsiderately put such a prince over them as their head? It was perfectly evident such a prince would rule the Germans to their injury, and under the cover of zeal for the faith, abuse their confidence and rob them of the Word of God.” – Huldrych Zwingli
So Zwingli on the eve of the election of Charles V as Holy Roman Emperor in 1519 in an appeal to the Swiss Cantons to refrain from participating in the doings of the Emperor and the Empire.
Zwingli was right to distrust Charles.