(John Christopher), one of the greatest theoretic musicians of modern times, as we are told, was born at Berlin about 1667; and became so early a proficient on the harpsichord, that at the age of 14 he was sent for to court, and appointed to teach the prince, father of the late King of Prussia. About 1700, he came over to England, and was retained as a performer at Drury Lane: it is supposed that he assisted in composing the operas which were performed there. While he was thus employed, he forebore not to prosecute his private studies; and these led him to enter into the music of the ancients, and the perusal of the Greek authors upon that subject. The abilities of Pepusch, as a practical composer, were not likely to become a source of wealth to him: his music was correct, but it wanted variety of modulation. Besides, Handel had got possession of the public ear, in the opinion of whose superior merit he readily acquiesced; and chose a track for himself, in which he was almost sure to meet with no obstruction. He became a teacher of music, not the practice of any particular instrument, but music in the absolute sense of the word, that is to say, the principles of harmony and the science of practical composition; and this, not to children or novices, but in very many instances to professors of music themselves.

In 1713, he was admitted to the degree of Doctor in Music at Oxford, and continued to prosecute his studies with great assiduity. In 1724, he accepted an offer from Dr Berkeley to accompany him to the Bermudas, and to settle as professor of music in his intended college there; but the ship in which they sailed being wrecked, he returned to London, and married Francesca Margarita de PEpine. This person was a native of Tuscany, and a celebrated singer, who performed in some of the first of the Italian operas that were represented in England. She came hither with one Greber, a German, and from this connection became distinguished by the invidious appellation of Greber's Peg. Afterwards she commenced a new connection with Daniel Earl of Nottingham, who had defended the orthodox notion of the Trinity against the heretic Whitton; and to this connection Rowe, in imitation of Horace's, Did not base Greber's Peg inflame The sober Earl of Nottingham, Of sober fire descend? That, careless of his soul and fame, To play-houses he nightly came, And left church undefended.

She continued to sing on the stage till about 1718; when having, at a modest computation, acquired above ten thousand guineas, she retired from the theatre, and afterwards married Dr Pepusch. She was remarkably tall, and remarkably worthy; and, in general, of defective personal charms, that Pepusch seldom called her by any other name than Hecate, to which she is said to have answered very readily.

The change in Pepusch's circumstances by Margarita's fortune was no interruption to his studies: he loved music, and he pursued the knowledge of it with ardour. At the instance of Gay and Rich, he undertook to compose, or rather to correct, the music for the Beggar's Opera. His reputation was now at a great height. He had perused with great attention those several ancient treatises on Harmonics, published by Meibomius, and that of Ptolemy by Dr Wallis; and the difficulties which occurred to him on the perusal, were in a great measure removed by his friend De Moivre the mathematician, who assisted him in making calculations for demonstrating those principles on which the harmonic science is founded. In consequence of these studies, he was esteemed, in matters of theory, one of the best musicians of his time. In 1737, he was chosen organist of the Charter-house, and retired, with his wife, to that venerable mansion. The wife died in 1740, before which he lost a son, his only child; so that he had no source of delight left, but the prosecution of his studies, and the teaching of a few favourite pupils, who attended him at his apartments. Here he drew up that account of the ancient genera which was read before the Royal Society, and is published in the Philosophical Transactions for October, November, and December, 1746; and, soon after the publication of that account, he was chosen a Fellow of the Royal Society.

He died the 26th of July, 1752, aged 81; and was buried in the chapel of the Charter-house, where a tablet with an inscription is placed over him.