The Protestant Church of Peace (German: Friedenskirche) is situated in the Marly Gardens on the Green Fence (Am Grünen Gitter) in the palace grounds of Sanssouci Park in Potsdam, Germany.

The church was built according to the wishes and with the close involvement of the artistically gifted King Frederick William IV and designed by the court architect, Ludwig Persius.

The church is located in the area covered by the UNESCO World Heritage Site Palaces and Parks of Potsdam and Berlin.

He gave his court architect Ludwig Persius two main instructions: The church was to derive in form and size from the early Christian Basilica di San Clemente in Rome.

The religious Frederick William IV desired a flat coffered ceiling on the inside, with gold stars on a blue base painted on the panels.

He was trying to establish a reconciliation between the Protestant majority of the original Prussian state and the Catholics of the more recently acquired lands, notably in the Rhineland Province.

On the semicircle of the apse a Latin inscript reads, according to Martin Luther's translation: "Lord, I have love for the site of your house and the place where your glory resides".

The altar canopy, which rests on four dark green columns, was created from Siberian jasper (semi-precious stones) and was a gift from Tsar Nicholas I of Russia, the king's brother in law.

Under two marble tablets, embedded in the ground in front of the steps of the altar room, the royal crypt can be found.

Both coffins, made out of English tin, carry the same inscript as the marble plates in the church floor: "Here he rests in God, his Redeemer, in the hope of resurrection in the soul and a merciful judgement, justified solely by the service of Jesus Christ our most holy Saviour and Only Life".

In the year of the crypt's dedication, the flooring of the church was completed as Frederick William IV had wished; the design is an intricately interleaved endless ribbon which represents eternity.

The larger-than-life statue of Christ on the fountain is a copy of the marble original, created in 1821 by Bertel Thorvaldsen, in the Copenhagen Church of Our Lady.

The plans were drawn up by Julius Carl Raschdorff, who also designed the Berlin Cathedral from 1893 to 1905, in the style of the Baroque-influenced Italian High Renaissance.

In the middle of the rotunda stands the marble sarcophagus of German Emperor Friedrich III and his wife Empress Victoria, formerly Princess Royal of Great Britain and Ireland.

Originally entombed in the now destroyed Garrison Church in Potsdam, like his son Frederick the Great, the coffin was moved shortly before the end of the war in 1945.

It is a replica of a Roman tiered porch at the former refectory in the Heilsbronn Cloister in Middle Franconia, which caught the eye of the architect Ludwig Ferdinand Hesse while he was on a study trip in 1828.

The original from the Heilsbronn Cloister was brought to the National Germanic Museum in Nuremberg, where it was almost entirely destroyed at the end of the Second World War in 1945.

The compact planting of groups of trees and bushes, access balconies, flower beds and sculptures reflect a picture of romantic playfulness.