Palác Colloredo-Mansfeld, Baroque palace in Old Town, Czech Republic.

The Colloredo-Mansfeld Palace is a four-winged baroque building at Karlova 189/2 in Prague's Old Town, not on Old Town Square. Its two-storey main facade has a high-baroque portal with vases, putti and the Colloredo-Mansfeld coat of arms, attributed to Antonín Braun. The wings enclose a rectangular courtyard with a sandstone Neptune fountain from around 1735.

A Romanesque house, later Gothic, stood here before a late-Renaissance rebuild; in the night of 8 to 9 November 1620 the royal council of Frederick of the Palatinate met here after the Battle of White Mountain. Count Breda began the high-baroque reconstruction around 1700, probably designed by Giovanni Battista Alliprandi and completed by František Ignác Prée for Count Jindřich Pavel of Mansfeld, who bought the palace in 1735.

The palace is named after the Colloredo-Mansfeld family, who acquired it in 1848 as the dowry of Princess Vilemína Josefína; she had the facade and interiors reworked in the neo-rococo style after Viennese models in 1853. The building now belongs to the City of Prague and is administered by the Prague City Gallery, which plans its reconstruction for cultural use; it is only partly open to the public.

The building sits in the heart of the Old Town and is easily reached by public transport, especially metro line A to Staroměstská station or trams 2, 17, and 18. Its central location means visitors can walk through the narrow streets and squares of the historic district.

The ceiling fresco in the first-floor oval ceremonial hall shows the assembly of the Olympian gods; it was painted by Pietro Scotti with architectural quadrature by Giovanni Battista Zaist. The palace's top floor once housed the Royal Bohemian Provincial Estates fencing school, closed in 1914 after the death of Gustav Hergsell Jr., the last provincial fencing master.