The fact that Luxembourg did not become a diocese until 1870 is mainly due to the political situation with frequently changing dependencies under other rulers. Intense striving for ecclesiastical autonomy began in 1443 after the Duke of Burgundy conquered Luxembourg. Efforts failed however due to the resistance of the prince bishops of Liège and Trier. As part of the personal union of the Grand Duchy with the Netherlands, Luxembourg was annexed to the diocese of Namur in 1823. After the Treaty of London (1839), a separate Apostolic Vicariate was established for the diminished Grand Duchy in 1840. In 1870, Nicolas Adames finally became the first Bishop of Luxembourg.