The current church, a baroque building around 100 metres (328 ft) long, was built from 1668 to 1693 after a fire in 1662 destroyed its predecessor, of which only the late gothic eastern side remains.

[2] The cathedral's overall plan was made by Carlo Lurago, its interior decoration by Giovanni Battista Carlone, and its frescos by Carpoforo Tencalla.

Over time, it has been outgrown by more recent instruments, for instance Wanamaker's organ in the USA.

The organ currently has 17,774 pipes and 233 registers, all of which can be played with the five-manual general console in the gallery.

In 2017, Arnold Schwarzenegger was allowed to play the cathedral's pipe organ, a "childhood dream" according to the actor.