The Church of Sant'Alessandro Maggiore in Lucca was mentioned for the first time in the year 893. In 1071, Alexander II, pope and Bishop of Lucca, moved the body of St. Alexander I from Rome to Lucca, and for the occasion, the now-filled-in crypt was built. The decision to move the body attested to the tight bond that the pope had maintained with the city and the consideration that he held for his historic predecessor, from whom he took his papal name.
The extraordinary architectural peculiarities of the building have aroused interest from critics, who consider it one of the architectural precursors of the 11th century. In the 1200s, the church was given a role of great civic importance, hosting the Curia dei Foretani, that is, the court for Lucca tasked with judging debates between the townsfolk and farmers.
In the 16th century, the building was covered with a rib vault, the crypt was filled in and the body of St. Alexander was moved to the high altar, while wider windows were opened in the naves. In 1840, the church underwent an important restoration commissioned by Duke Carlo Lodovico: the interventions were expertly led by Lorenzo Nottolini, while Michele Ridolfi painted the apse, using the hot wax technique.