Complex sentence: Licinia was tried on an almost certainly trumped-up charge of broken chastity, acquitted, then re-tried, found guilty, and executed on the strength of two prophecies in the Sibylline books.
Split into simpler sentences: Licinia was tried on an almost certainly trumped-up charge of broken chastity, but acquitted. She was re-tried, found guilty, and executed, on the strength of two prophecies in the Sibylline books.