"M. Johann Gottfried Müthel of Riga, being by birth and education a German, deserves a place here, though he is at present established in a city which appertains to Russia. When a student upon keyed instruments has vanquished all the difficulties to be found in the lessons of Handel, Scarlatti, Schobert, Eckard, and C.P.E. Bach; and, like Alexander, laments that nothing more remains to conquer, I would recommend to him, as an exercise for patience and perserverence, the compositions of Müthel; which are so full of novelty, taste, grace, and contrivance, that I should not hesitate to rank them among the greatest productions of the present age... The style of this composer more resembles that of Emanuel Bach, than any other. But the passages are entirely his own, and reflect as much honour upon his mind as his hand. Indeed his writings abound with difficulties, which to common hearers, as well as common players, must appear too elaborate; for even his accompaniments are so charged as to require performers, for each instrument, of equal abilities to his own, which is expecting too much, in musicians of this nether world."
Charles Burney. "A General History of Music" (1776)