Complex sentence: On the architrave there was a frieze of garlands and bukrania and the entablature was surmounted with a tympanon which had an epiphania window (at which god showed himself to the people) in the middle which was surrounded with lotus and palmet leaves.
Split into simpler sentences: On the architrave there was a frieze of garlands and bukrania. The entablature was surmounted with a tympanon which had an epiphania window (at which god showed himself to the people) in the middle, surrounded with lotus and palmet leaves.