The old town, however, always contained a strong Bohemian-Slavic element, and the fusion of the two nationalities undoubtedly became closer when, during the reign of King Wenceslas I., the old town was--probably about the year 1235--enclosed with walls. These walls starting from the Vltava, near the present bridge of Francis Joseph, followed the line of the Elizabeth Street and the Josefské Námesti till they reached the Prikopy or Graben. Thence they proceeded along the present Prikopy, Ovocná ulice and Ferdinandova ulice till they rejoined the river, near the spot where the national theatre now stands. The Graben, now the principal thoroughfare of Prague by its name, which signifies ditch or trench, still recalls its original destination. The Prasná Brana (powder tower or gate) marks the spot where one of the gates of the old town stood. According to Dr. Tomek the fortifications consisted of a double wall and double ditch, which was filled with water derived from the Vltava. With the exception of the Vysehrad and a few straggling buildings near the present Poric Street, the new walls contained all that part of Prague that was situated on the right bank of the river. Premysl Ottokar II., the son and successor of Wenceslas I., was one of Bohemia's greatest kings. Both by successful warfare and by skilful diplomacy he so greatly enlarged his dominions, that his rule at one time extended from the Adriatic in the South to the Baltic in the North. Though his many campaigns left him little leisure to reside in his capital, Ottokar enlarged both the town and the fortifications of Prague. In 1257 he greatly added to the fortifications that no doubt already existed on the Hradcany Hill. He caused the whole Hradcany Hill to be surrounded by a strong wall and the various towers to be connected by covered passages. Ten knights and 300 armed men were to keep constant watch and ward over the fortifications. The still existent towers--Daliborka, Mikulka, and the white and the black towers--formed part of these fortifications. Somewhat later the King also enclosed with walls the Malá Strana (small quarter)--that is to say, the buildings that extended from the foot of the Hradcany to the river. Here fortifications were necessary in three directions only, as in the direction of the Hradcany that fortress protected the newly enclosed settlement. It appears probable that when the old town had been fortified a tête-de-pont had been built on the left bank of the Vltava, which, together with a similar building on the right bank, was to secure the bridge of Prague. The fortified gate on the left bank was now included in the new fortifications. It may here be remarked that when the old town had been fortified the Jewish quarter (vicus Judæorum) had been included in these fortifications; gates, however, separated the Jewish quarter from the rest of the old town.