The hamlet of Trobaso and its parish church, the Chiesa di San Pietro, are flanked on one side by the San Giovanni torrent which flows into the Intrasca valley and on the other the San Bernardino river that flows into the Val Grande. Over the centuries, the church had become a religious landmark for the faithful of the surrounding valleys.

Testimony to this is an early Romanesque construction, the existence of which is cited in a manuscript dated 1031. The building consisted of two vaulted naves, both completed with apses, while the bell tower was probably tangential to the north nave which no longer exists.

The current building was rebuilt between the 16th and 17th centuries, a period in which, for reasons of space, the main nave was demolished and replaced by a much larger one. The northern nave and the four-storey bell tower remain from the Romanesque period, with the characteristic structure of double-blind arches on each side.

It is well worth entering the church to admire the fine seventeenth-century carved wooden furnishings, notably the pulpits by Antonio Pino and the spectacular pyramid-shaped tabernacle: an 8-metre-high golden altar, carved with intricate twisted columns, tympanums and domes, resplendent with statues, built in the first half of the seventeenth century by engraver Bartolomeo Tiberino from Arone. A living example on all the sumptuousness that the Baroque sought to represent.

An ongoing restoration campaign is bringing to light significant traces of frescoes ascribable to the first half of the sixteenth century.