The group, passed by descent, is led by this Egyptian bronze Horus falcon sarcophagus estimated at £1500-2500.
It dates to the Late Period (c.664-332BC) and measures 5½ x 7in (14 x 18cm).
After a hand injury left him unable to perform surgery, Mainzer became a writer on antiquity, penning a well-respected biography of Julius Caesar which was translated into French and English. He later became involved with the aristocratic Roman Catholic Solf Circle, a group of intellectuals involved in the resistance against Nazism.
Mainzer and his family escaped to England with the help of the Countess Lagi von Ballestrem-Solf, who escorted them with the family’s jewellery hidden in the lining of her clothes.
A portrait of Mainzer painted in 1899 by Lovis Corinth is currently on loan to the National Gallery in London.