Though government business in Germany today is done in German this hasn't always the case. I'm aware of the fact that German had a bad reputation in the early modern period, epitomised by the Charles V quote, "I speak Spanish to God, Italian to Women, French to Men, and German to my Horse." While Charles V lived a century before the 30 years war, the impression it gives is that French was the official language of government. Despite this, important political documents like the treaties that made up the Peace of Westphalia were written in Latin, giving the impression that it was the language of government. This leads me to wonder, what language would the business of governance have been carried out in, both in terms of spoken negotiation and written laws/treaties?