The Caldereros -Spanish for boilermakers- party originated on the 2nd of February in 1884, a year when the Hungarian carnival group of Caldereros paraded for the first time in San Sebastian. There is some evidence of carnival records in the 19th century, but it was not until the above-mentioned date that tradition was made official in the way it is celebrated today, year after year, on the first Saturday of February or the Saturday prior to Candelaria festivity.
The associations Union Artesana and La Fraternal were the ones to start the tradition, which was, in turn, continued by many others later on. The Caldereros celebration had an irregular audience throughout the years until, in 1924, it was recovered by the Gaztelupe association. They changed the schedule of the party so that the most significant part of the festival took place in the evening. This way, everyone could enjoy it, no matter if it was a working day. In spite of the efforts made to perpetuate this celebration, it fell into decline once again, but finally re-emerged thanks to the Gaztelubide association in 1942.
The most significant change was introduced in 1962, when the festival started to be celebrated on the first Saturday of February insted of on Candelaria festivity. Thus, it always coincided with a holiday and people could enjoy the party without any worrying.
Between 1969 and 1971, the festival was not celebrated for political reasons, but it had its definitive come-back in 1972 and it has remained up to our days thanks to the support received from the San Sebastian tourism centre.