We now come to London Bridge, the great southern approach to London, and the most important strategical position, as when that was fortified the inhabitants were safe from attack on the south. Passing westward from the bridge we come to the Old Swan Stairs, the Steelyard, Coldharbour, Dowgate and the Vintry, and then we come to Queenhithe, said to have been named after Eleanor, widow of Henry II., to whom it belonged. It was previously known as Edred's hithe. Passing Paul's Wharf, we come to the vast building known as Baynard's Castle, built by Humphry, Duke of Gloucester, in 1428. This mansion had an eventful history until it was destroyed in the Great Fire. A previous Baynard's Castle was situated on the Thames nearer the Fleet River, and was named after Ralph Baynard, one of the Norman knights of William the Conqueror. It afterwards came into the possession of Robert Fitzwalter, chief bannerer or castellan of the city of London. When the Dominicans or Black Friars removed from Holborn to Ludgate they swallowed up in their precincts the Tower of Mountfichet and Castle Baynard, which were the strongholds built at the west end of the city. Edward I. allowed the friars to pull down the city wall and take in all the land to the west as far as the River Fleet. Moreover, the King intimated to the Mayor and citizens his desire that the new wall should be built at the cost of the city. We here pass up to Ludgate, which does not appear to have been a gate of much importance until the beginning of the thirteenth century. The idea that it is named after a mythical King Lud is, of course, exploded now, and there are at present two etymologies to choose from. Dr. Edwin Freshfield supposes the name to be derived from the word lode, a cut or drain into a large stream. The main stream of the Fleet passes from the Thames to the foot of Ludgate Hill, but a short branch went in a north-eastward direction to Ludgate, joining there the town ditch. Mr. Loftie explains Ludgate as a postern, and supposes it to have existed in the Saxon period as a postern gate. All along the river front of London originally there was a wall, remains of which have been found at various times. Fitz-Stephen, writing in the twelfth century, says: 'London formerly had walls and towers ... on the south, but that most excellent river the Thames, which abounds with fish, and in which the tide ebbs and flows, runs on that side, and has in a long space of time washed down, undermined and subverted the walls in that part.'[22] Outside Ludgate the road to the west was not much frequented. Fleet Street and the Strand were not the important thoroughfares during the Middle Ages that Holborn was. The roads were much neglected, and no one traversed them who could travel by boat on the Thames, which was literally the Silent Highway of London.