It is a small church, built in the form of a cross.

The roof is supported by Corinthian columns, so disposed as to raise an idea of grandeur, which the dimensions of the structure do not seem to promise.

Over the centre, at which the principal aisles cross, is a dome divided into compartments, the roof being partitioned in a similar manner, and the whole finely decorated.

The effect of this build-ing is inexpressibly delightful; the eye at one glance embracing a plan full and distinct, and afterwards are seen a greater number of parts than the spectator was prepared to expect.

It is known and admired on the Continent, as a master-piece of art.