The fact that we today still have knowledge of the song, is due to the Spanish baroque composer Francisco Correa de Arauxo (1), who later wrote a piece for organ with variations, based on the popular melody. We decided to trace 'Todo el mundo' back to it’s original form as a song, and, at the same time, preserve Arauxo’s variations.
You can listen to the result here, while reading the fascinating story about el Canto Llano de la Inmaculada: Todo el mundo en general.

The use of popular song and music as a mean to support reforms, and to advocate for religious doctrines, was not exclusive to the Protestant Church. In beginning of the 17th century the Franciscan order in Spain worked determinedly on convincing the Holy See to raise the doctrine of “The Immaculate Conception”, La Inmaculada Concepción, to the level of Catholic dogma. Those efforts included both theological discussions, political lobbyism and social and popular mobilization, and in that latter context a simple religious song by the Sevilian composer and priest Bernardo del Toro (1570-1643), composed at Christmas time 1614, came to play a mayor role.
It is told that the composer gave a small party in relation with the traditional Christmas nativity scene, and that the visitors, including the friend and poet Miguel Cid, arrived at the party with ’songs and verses’. In this festive gathering the song dedicated to the “Immaculate Virgin” arose:

Todo el mundo en general 
a voces - Reyna escogida 
diga que soys concebida 
sin pecado original.

Let everyone lift up their voice
in chorus - chosen Queen -
that You are conceived
without original sin.

Variations on Todo el mundo

In 1625 the Spanish baroque-composer Francisco Correa de Arauxo published a treatise on organ playing, in which one of the last pieces, Tres glosas sobre el canto llano de la Inmaculada, is a set of variations on the famous tune by Bernardo del Toro and Miguel Cid. The piece is remarkable in many ways. First Arauxo presents the original song in the shape of a chorus followed by a verse, with the principal voice placed in the tenor. Then the chorus is presented again, this time with the principal voice held by the soprano. Subsequently the variations rise in speed and level of difficulty. The variations run twice over the verse part while the third and last time, the quickest, is based on the chorus.

Todo el mundo, revisited

Arauxo’s melody is very similar to the original composed by Bernardo del Toro (3), thus we decided that we would not offend against any of the composers’ posthumous reputation by re-arranging the piece as a song, using the original text, while at the same time keeping Arauxo’s variations.
Arauxo’s variations run over the exact length of both choruses and verses, but in the 2nd variation a line is missing. In the original song (as in the 1st variation) the last line of the verse is repeated where the lyrics read “sin pecado original’, but in the 2nd variation this repetition is absent. Unfortunately it’s not possible to know whether the missing line is due to a mistake in the publishing process, or if Arauxo consciously omitted the repetition of the last line, but for the sake of wholeness we decided to add the missing line - with the lack of respect for original compositions that practitioners of early music must show from time to time, just as the musicians of the baroque era themselves so fully practised. The variations on the second last line in this 2nd variation consequently do not originate from Arauxo’s hand.
You can listen to the result of the reconstruction here:

• First the chorus is sung, and right after that, the verse called copla.
• Then the chorus is played by the bass viol, followed by the 1st variation on the verse, played by the portative organ.
• Then follows the 2nd variation on the verse, played by the bas viol, and finally the song ends with the 3rd variation on the chorus, played by the portative organ with added vocal on the last part.

Listen to the piece and note how Arauxo’s variations elegantly play with the constant change between duple and triple metre.
 
1) Spanish organist and composer, possibly of Portuguese descent. Organist at the Church of S. Salvador in Seville from 1599 until 1636, then at Jaén Cathedral until 1640, finally at Segovia Cathedral until his death. His Libro de tientos y discursos de música practica, y theorica de organo, intitulado Facultad organica (Alcald, 1626) contains 62 tientos and seven other pieces, all for organ, introduced by a theoretical treatise and arranged in order of increasing difficulty, in a colorful baroque style, with bold dissonances and wayward figurations.
(2) In Spain The Feast of the Immaculate Conception still is celebrated on the 8th of December
3) Bernardo del Toro’s song is a so-called canto llano, i.e. a song in a modal church tonality, Arauxo adds to the song an early baroque harmonization. The rhythmical alternation between two- and tripartite metre originates from the original tune by Bernardo del Toro.