The extant documentation on this organ allows us to state with a certain degree of confidence that, at least from the period 1469-1474 up until the present day, the external features of the instrument have changed very little - the Gothic case - and even, in some ways, the fact that the organ was originally conceived as the sum of three organs. The case has not been altered for the last 150 years.
We can divide the history of this organ into four periods according to what different organ builders did or what type of work was done on it between the 15th - 19th centuries.
1) The "Gothic" Organ by Johan Ximénez Garcés or Johan de Berdún ( from 1469 on). This 15th century instrument was already conceived in modern terms, with differences (the stops) on some of its manuals, as opposed to earlier medieval tendencies.
2) The "Renaissance" Organ by Gullaume de Lupe ( from 1577 on) who brought all the stops of the different divisions together onto one manual. De Lupes son, Gaudioso, may have been the one who added the first divided stops (registros partidos) in 1610.
3) The "Baroque" Organ by Joseph Sesma (in two phases): the first one in 1681; he began a second phase in 1693/94, but was unable to complete it since he died in 1699. Sesmas work was finished, however, in 1720 by Bartolomé Sánchez, and in 1755, Silvestre Thomás continued with further work. In the 18th century the organ adapted its possibilities to the exuberant sound aesthetics of the Baroque Period.
4) The organ today. The instrument we hear and see today is the product of Pedro and Miguel Roqués (1857). In spite of the Romantic sound that was prevalent throughout Europe at the time, Roqués built a classic style organ with a few novel stops such as the Euphone. Juan Roqués made a few more minor changes in 1919.
