Kathleen Schlesinger, 1911 Encyclopædia Britannica, Volume 22… (1911)
“ A well-known instance of an early positive or portable organ of the 4th century occurs on the obelisk erected to the memory of Theodosius the Great, on his death in A.D. 395. Among the illuminated manuscripts of the British Museum miniatures abound representing interesting varieties of the portable organ of the middle ages ”
