It was realised about 100 years ago that surgical treatment to overcome the fixation of the stapes should be possible; some early attempts were made but foundered in the absence of microscope magnification and antibiotic therapy. It was only in modern times that surgery for otosclerosis became a reality. An operation to fenestrate deliberately the lateral semi-circular canal through a mastoidectomy approach was originated before the Second World War and performed for a number of years. It created an alternative channel for sound which bypassed the fixed stapes and led to hearing improvement in severe cases, although the benefits of operation were usually lost after a number of years. Patients are still seen who had fenestration in the 1940s and 50s, and in some cases the hearing has been reasonably maintained. In 1956 Rosen mobilised the stapes to produce a hearing gain; operations for stapes mobilisation were performed regularly for a short period thereafter, but it was found that the stapes rapidly refixed itself.