The young Gaudí had worked as a draftsman of the architect Del Villar, in building the new apse of Montserrat. The entire basilica was redecorated in the following years. The Piarist Fathers took over a monumental altar dedicated to St. Joseph of Calasanç, as the residence of its saint founder in Montserrat was a significant episode of his biography. They went in 1891 to Gaudí, who, very busy, it did draw his assistant. Francesc Berenguer was only twenty-five years old and Gaudi could have used as "black" assistant, as it had happened to him in the apse, but he wanted Berenguer, then a family’s father, appeared as head of the commission. The altar and the altarpiece, flanked by the coats of Catalonia and Montserrat, are cedar, largely without polychrome, with the crucifix, candlesticks, lamps and other attachments by iron. The altarpiece, which highlights the image of the saint, consists of seven horizontal bands of gold decoration, which recalls the "katagami" Japanese. The set is a piece fully of “Modernisme” stile, beautiful, and it can be said that with this altarpiece came in Montserrat the Catalan Modernisme more genuine.