In 1803 the Duchy of WÃ 1\/4 rzburg became part of Bavaria , in 1938 the city had more than 100,000 inhabitants for the first time . The city passed to the Electorate of Bavaria in 1803 , but two years later , in the course of the Napoleonic Wars , it became the seat of the Electorate of WÃ 1\/4 rzburg , the later Grand Duchy of WÃ 1\/4 rzburg .