A Polish religious group is trying to stop Madonna from performing a sold out concert in Warsaw.

The Committee for the Defence of the Faith and Tradition is protesting the Material Girl’s plans to play her first ever concert in Poland. The event, set for August 15, falls on a holy day for the Virgin Mary that is regularly observed by Roman Catholics in the country.

The Committee vows to carry on its “crusade” against all things Madge.

“We’re going to continue our crusade with daily prayer sessions outside Warsaw city hall from August 1,” said Marian Brudzynski, head of the Committee. “We’ll start with a group of a few hundred people but I’m convinced that the square in front of city hall will end up filled with pious Poles.”

The group is asking Warsaw’s city hall to block the sold out event, which is expected to draw more than 70,000 fans.