The idea of creating a Diocesan Museum came about at the beginning of the 20th century when the first pieces of the collection began to come together on the premises of the Episcopal Palace. Throughout this time it has had several homes: in 1923, a “diocesan museum” was opened at the Conciliar Seminary, where objects of art belonging to the churches were duly classified; Between 1930 and 1936 it was housed in the new Diocesan Seminary and between 1942 and 1999 it formed part of the collection at the Palace of Agustín under the subsequent museum institutions of the House of Álava, the Provincial Museum and the Museum of Fine Arts.
Finally, in 1999, this museum was opened in the New Cathedral with the aim of restoring, preserving, studying and disseminating the religious heritage of the Diocese and the Historical Territory of Álava.
The pieces that go to form the collection have come from the Provincial Council of Álava, the Bishopric of Vitoria and the churches of the Diocese and are displayed in five sections arranged chronologically and named according to the predominant materials or techniques used: Stone, Wood, Panels, Canvas and Silver
The Museum is located in the New Cathedral, a Neo-Gothic building that began construction in 1907, but was halted between 1914 and 1946 and was consecrated in 1969. Its interior is very open and it has five high naves illuminated by magnificent stained-glass windows created by the Maumejean family. The spiritual and that of the museum coexist in the temple given that the chapels of the ambulatory have become the rooms for the museum.