invasion at Boulogne. The one on the Eastern Heights still stands in the grounds of Dover Castle to 80 feet (24 m) high close to its original height, and has been adapted for use as the bell tower of the adjacent castle church of St Mary de Castro. This Roman Pharos has been a Grade I-listed building since 1974. What little remains of the western lighthouse is called the Bredenstone or the Devil's Drop of Mortar after the putative nearby lost village of Braddon, within Drop Redoubt on Dover Western Heights – it was covered in the 18th-century building works but then rediscovered in fresh works in the 1860s, and was the traditional site of the investiture of the Lord Warden of the Cinque Ports. Peak At its peak, Dubris was a major trading centre, taking over from Rutupiae as the main Roman cross-Channel port. With Rutupiae, it was one of the starting points for Watling Street, the Roman road to Canterbury and, ultimately, London. Roman Painted House During the construction of the new A256/York Street bypass in the 1970s, Roman remains were discovered and an eight-week excavation followed. The archaeologists discovered a Roman mansio now known as the "Roman Painted House". The mansio, a hostel for government officials, was built in c. 200. It was discovered in 1970 by the Kent Archaeological Rescue Unit and, as it houses some of the finest example of Roman murals in Britain (over . of painted plaster, the most extensive ever found north of the Alps), it has been called "Britain's Buried Pompeii". Above a lower dado of red or green, an architectural scheme of multi-coloured panels framed by fluted columns is still visible. The columns sit on projecting bases above a stage, producing a clear 3D effect. Parts of 28 panels survive, each with a motif relating to Bacchus, the Roman god of wine. This Bacchic link, and the building's proximity to the baths, port and fort, has been said by some to suggest that the Painted House was once a brothel. However, this is entirely circumstantial evidence (frescoes in brothels tended to be more explicit, as in those at Pompeii, and Bacchic motifs are very commonly found in simply domestic areas) and so most academics believe the rooms are too small to have supported this line of work and instead support its designation as a mansio. Other features of the Painted