He was the son of
Prince Friedrich Leopold of Prussia and
Princess Louise Sophie of Schleswig-Holstein-Sonderburg-Augustenburg, and a nephew of
German Empress Augusta Victoria, his mother's elder sister. Originally trained by tutors, at the age of ten, as was customary, he received the
Order of the Black Eagle. The following year, he became a Lieutenant in the
First Foot Guards. In 1912, he became interested in painting, and took drawing lessons from
Karl Hagemeister. At the outbreak of
World War I, he started his military service, but was soon discharged due to poor health. This enabled him to attend the
Academy of Fine Arts, Munich, where he studied with
Carl von Marr, among others. He also began collecting art. His unrestrained collecting put him heavily in debt. As a result, in 1917, the initiated an "" (incapacitation procedure), with the intent of placing him under a
guardianship. The Prince filed a
counter-suit, claiming that his collection had appreciated in value, and was now worth as much or more than the amount he owed. In addition, he argued that the Ministry had no
standing in the matter of civil suits. In 1918, following widely publicized hearings, which reached the
Kammergericht (Berlin State Supreme Court), the Ministry agreed to halt its proceedings. In the 1920s and 1930s, he continued collecting and worked as an art dealer; trading in art objects and autographs from the collection of his great-grandfather,
Prince Charles of Prussia. As he had a right of residence at
Glienicke Palace, he made the assumption that he had property rights there as well. He lived with his private secretary, Friedrich Freiherr Cerrini de Monte Varchi (1895–1985), known as "
Pierrot", in the "gentleman's wing" of the Palace. One of his best clients was the American diplomat and collector,
Robert Woods Bliss. One of the pieces that Bliss purchased in 1937, a 12th-century
Byzantine tondo from the Palace's monastery courtyard, led to a criminal investigation and proceedings at the , which resulted in heavy fines for the Prince and Cerrini. After selling the castle in 1939, he and Cerrini moved to a villa, "Gut Imlau", near
Werfen in
Salzburger Land. He took numerous art works and the family archives with him. The remainder was bequeathed to the
Prussian Palaces and Gardens Foundation Berlin-Brandenburg.
Dachau The prince was rumored to be homosexual, and in 1941, the German diarist
Friedrich Reck-Malleczewen recorded that Friedrich Leopold was being periodically arrested by Nazi officials in order to extort money from his mother, of whose four children Friedrich was the only survivor. In May 1944, he and Cerrini were arrested in
Bad Gastein for listening to a "
Feindsender" (enemy radio station). Some sources claim they were actually charged with violating "
Section 175", which prohibited homosexual activity. Later that year, the Prince was remanded to Dachau. In 1945, he was part of a group of high-status prisoners and
Sippenhaften (people guilty by kinship), who were
transported to South Tyrol by the
SS. A few of the prisoners managed to contact officers of the regular German Army and express their fears that they were going to be executed. They were rescued by Captain
Wichard von Alvensleben and took refuge until American troops arrived. The Prince waited until June, so he could be available to American officials in Italy. In the first of the
Dachau trials, he served as a witness against numerous camp officials, including the Commandant,
Martin Gottfried Weiss. Forty of them were found guilty, and thirty-six were sentenced to death. He never returned to Germany, choosing instead to settle in Switzerland. He died fourteen years later, on 27 November 1959 in
Lugano, aged 64. His body was buried in the Cimitero di
Castagnola, Lugano, Switzerland. == Ancestry ==