In the following centuries the edifice underwent several restorations and partial reconstructions, assuming the current appearance in 1099, when it was rebuilt in Romanesque architecture.

he basilica has two bell towers. The right one, called dei Monaci ("of the Monks"), is from the 9th century and has a severe appearance. The left and higher one dates to 1144, the last two floors added in 1889.

The church also houses the tomb of Emperor Louis II, who died in Lombardy in 875.

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