As of 31 December 2006, with 4.336 million adherents or 47.1% of local population, nearly half the inhabitants of the Münster diocese were Catholic; due to continuing secularisation, this a decreased percentage compared to earlier periods.

Freiherr von Fürstenberg administered as vicar-general the ecclesiastical affairs of the diocese even during the short supremacy of the French (1806-13).

In the years 1813-15 the diocese was administered, without the authorization of the pope, by Count Ferdinand Augustus von Spiegel, arbitrarily appointed by Napoleon, and to whom Droste-Vischering had given his faculties by subdelegation.

On account of illness, he left the administration to Jodok Hermann von Zurmühlen, already an old man, whom he made pro-vicar.

[4] During the episcopate of John Gregory Müller (1847-70), fruitful popular missions were held in many places, many churches were rebuilt, and a large number of religious houses and benevolent institutions were founded with the active assistance of the laity.