Christian was a Protestant pastor and one of the leading figures and organisers of the 1989 Monday demonstrations in East Germany which finally led to German reunification and the end of the GDR in 1990.

The Monday demonstrations were a series of peaceful political protests against the government of the German Democratic Republic (GDR) that took place in towns and cities around the country on various days of the week from 1989 to 1991. The Leipzig demonstrations, which are the best known, took place on Mondays. The protests are conventionally separated into five cycles.