In 1685 Margrave Frederick William of Prussia issued the Edict of Potsdam within a week after French king Louis XIV's Edict of Fontainebleau, that decreed the abolishment of the 1598 concession to free religious practice for Protestants. Frederick William offered his "co-religionists, who are oppressed and assailed for the sake of the Holy Gospel and its pure doctrine...a secure and free refuge in all Our Lands". Around 20,000 Huguenot refugees arrived in an immediate wave and settled in the cities, 40% in Berlin, the ducal residence alone. The French Lyceum in Berlin was established in 1689 and the French language had by the end of the 17th century replaced Latin to be spoken universally in international diplomacy. The nobility and the educated middle-class of Prussia and the various German states increasingly used the French language in public conversation in combination with universal cultivated manners. Like no other German state, Prussia had access to and the skill set for the application of pan-European Enlightenment ideas to develop more rational political and administrative institutions. The princes of Saxony carried out a comprehensive series of fundamental fiscal, administrative, judicial, educational, cultural and general economic reforms. The reforms were aided by the country's strong urban structure and influential commercial groups, who modernized pre-1789 Saxony along the lines of classic Enlightenment principles.