The steep cliffs jutting out above the sea, and bordering the shoreline have formed the small coves in the harbour of Split. One has been formed exactly in front of the Palace, and two other ones to the west and to the east of the Palace, respectively. The site of Diocletian's Palace had been laid out following the original configuration of the terrain, so the facade of the Palace was protected from the south-wind waves by the promontory of the eastearn cove. In 1986, the stone blocks of the Roman quay were excavated on the site in front of the Palace. (The Roman quay can be even seen on the cadastral maps of Split dating back in 1831). In the Middle Ages there was a small pier right in front of the southern gate of the Palace, where the ships coming to the Split harbour were moored. Among the first medieval structures erected at the waterfront, close to the Palace, was the wall running from the southeastern tower of the Palace (so called Archbishop's Tower) towards the seafront, and which was mentioned in the municipal Statute from 1312. The similar wall was erected to the west of it, so the whole space in front of the Palace, i.e. the city itself was protected by walls. As Split was developing toward the west, there was another gate that was leading to the city harbour, opened by the western tower of the Palace, so called Sea gate or Porta Marina. On the other hand, the Gate of the grotto, the most ancient passage to the seafront dating from Roman times, and located in the middle of the southern facade, was still used during the Middle Ages. In 15th century, during the Venetian rule, the Venetian garrison was housed in a newly erected Castle (Citadel) on Riva, similar to those that had already been built in all other major cities on the coast. Thus, the Venetian government protected the city and ensured itself against possible riots incited by discontented citizens.