Jacob Philadelphia was a magician, physicist, mechanic, juggler, astrologer, alchemist and Kabbalist. Born in 1734 or 1735, his birth name was Jacob Meyer. He was born in Wulfen but claimed to have been born in Philadelphia. Dr Christopher Witt, the associate of Johannes Kelpius, was chiefly responsible for his education. Meyer's patron in England was Prince Henry, Duke of Cumberland and Strathearn, for whom he performed astrology, magic and alchemy.
When he converted to Christianity, he took the name of Jacob Philadelphia in homage to the home city of American scientist and statesman, Benjamin Franklin. He was also known by the names Meyer Philadelphia and Philadelphus Philadelphia. Meyer became a member of the occult Rosicrucian order. After the death of his patron in 1756, he began to perform in public, exhibiting his skills in Ireland, Portugal and Spain. In 1771, he performed in St. Petersburg for Catherine the Great. Also, in Constantinople, he had Sultan Mustapha III as an audience. The year 1773 found him chasing away ghosts for Holy Roman Emperor Kaiser Joseph II, in Vienna at a charge of 300 Thalers. In Potsdam and Berlin, he had difficulty with Friedrich the Great, who was alarmed after Meyer read his mind. Friedrich was also averse to Meyer's Rosicrucianism and subsequently banished the magician from Prussia.
In James Randi's view, Meyer was probably the "first American-born ... magician to attain any fame". He was an early pioneer of phantasmagoria, a performance magic show with a focus on the appearance of ghostly figures. His shows involved "magic lantern, mirror effects and various magnetic and electrical (usually high-voltage) demonstrations."
The Little Treatise on Strange and Suitable Feats was written by Meyer in 1774. In 1758, he toured England. Although he presented himself as being a scientist, many took him for a magician. In 1777 he refused to lecture in Göttingen because of an extravagant, satirical poster campaign by Georg Christoph Lichtenberg who libelled him as being a magician and miracle-worker. Among other things, the poster was designed to make people think that they would be forced into harmful situations if they attended the lecture. Lichtenberg's Avertissement placard became widely known and damaged Meyer's career. His final lecture was given in 1781 in Switzerland. In 1783, he made a business proposition involving the use of occult powers to Frederick the Great, who declined the offer.
Meyer retired to Köthen, Germany, and died there at the turn of the century.
A biographical novel has been written by Marion Philadelphia in German about the life of Jacob Philadelphia. Its title is Der Gaukler der Könige (The Conjurer of Kings).