After undertaking the project in 1883, Gaudí built the crypt, which was finished in 1889. As he started work on the apse (and the cloister), everything went at a good pace thanks to the donations. When he received a large anonymous one, he thought of doing a new, bigger work: he discarded the old neo-Gothic project and proposed a more monumental and innovatory one in terms of both forms and structures and the construction. Gaudí's project consisted of a large church with a Latin cross ground plan and high towers; it carried a major symbolic load, in both architectural and sculptural form, with the ultimate aim of being a catechistic explanation of the teachings of the Gospels and the Church.
In 1892 he began work on the foundations of the Nativity façade because, as he said himself, "If, instead of making this decorated, ornamented and swollen façade I had begun with the Passion, hard, bare and as if made of bone, people would have stepped back." In 1894 the apse façade was finished and in 1899 the Roser door, one of the entrances to the Nativity cloister.
Alongside these works, at the south-west corner of the church, in 1909 Gaudí built the Temporary Schools, designed for the children of the workers on La Sagrada Família and the local children who were members of its parish. The following year, in 1910, a model of the Nativity façade was exhibited at the Grand Palais in Paris on the occasion of an exhibition of Gaudí's work, promoted by his friend and patron Eusebi Güell.