Blaise and John the Baptist) is a large Lutheran church in the City of Braunschweig (Brunswick), Germany.

In 1543, at the time of the Protestant Reformation, the City of Brunswick, in opposition to Duke Henry V of Brunswick-Wolfenbüttel, joined the Schmalkaldic League, and the church came into Lutheran use.

The cathedral lost possession of the collection in 1671 when the relics were removed by John Frederick, Duke of Brunswick-Lüneburg, Prince of Calenberg.

After the collection's designation as a national treasure in 2015, heirs of the art dealers brought common lawsuit(s) against Germany in U.S. courts in an attempt to recover perceived losses resulting from the 1935 sale.

Germany's motion to dismiss on the basis of jurisdiction and conflicts with the Foreign Sovereign Immunities Act was denied once, then again in an appeal.