Which preposition to use with westphalia

in Occurrences 5%

By the Treaty of Westphalia in 1648 Alsace and Lorraine went to France, and the rule of the great monarch, Louis XIV, had nothing to fear from the German peoples.

as Occurrences 1%

Therefore, the most innocent and the most daring trembled at the very name of the Free Judges of the Terre-Rouge, an institution which adopted Westphalia as the special, or rather as the central, region of its authority; the Council of Ten exercised their power in Venice and the states of the republic; and the Assassins of Syria, in the time of St. Louis, made more than one invasion into Christian Europe.

Which preposition to use with  westphalia