Of the parish churches of the Catholic rite that once existed in Candia, none has survived intact. Remains of some have come to light through excavation, can be traced embedded within later buildings, or are recorded in the photographic work of Giuseppe Gerola. The same holds true for most churches belonging to Catholic monasteries. The ducal church of St Mark, despite the many vicissitudes of its long history, is perhaps the best-preserved ecclesiastical monument of the Venetian period in Heraklion.