"Yes, Teresa," answered Herr Müller. "But it's a long jump from the Romans to Duke Heinrich. Several hundred years after the expulsion of the Celts from Vindobona, Charlemagne, the undaunted conqueror of the age, absorbed it into the German Empire; he distinguished it from the rest of the German Empire by giving it the name of the Eastmark or border of the empire (Oesterreich), hence Austria. He placed a lord or margrave over it; and when Conrad III of Germany became emperor, he appointed Heinrich Jasomirgott ruler over the Eastmark, giving him, at the same time, the adjoining territory of Bavaria. But he had no right to dispose of these Bavarian lands as he chose, just because he was angry with the Bavarians; and when his son, Frederick Redbeard (Barbarossa) came to the throne, he gave it back to the Bavarians. But Frederick Redbeard was a politic ruler; he did not wish to offend any of his subjects; in order to make up to Henry Jasomirgott for the loss of Bavaria, he raised him to the rank of duke, and thus Oesterreich or the Eastmark became a duchy. This was about 1100; then, being such an important personage, Duke Heinrich determined to make his home in Vienna. He built himself a strong castle, surrounded it with a high stone wall and a moat, as was the custom at that time, and included within it the confines of the city, so that he and his people might not be molested by neighboring princes. "Here," continued Herr Müller, as they passed to the end of the Platz, "is the Graben. To-day it is our most fashionable shopping district; but in the time of Duke Heinrich it was a moat filled with water; and here, where these rows of modern houses stand, were the ancient walls which protected the city." "Isn't it great!" cried Teresa, who, girl though she was, could appreciate the ancient struggles of her ancestors for liberty and defence. "Oh, father, there is Der Stock im Eisen!" said Ferdinand. "Tell Teresa about that, please; she doesn't know." "Der Stock im Eisen?" repeated Teresa. "What is it?" "That old tree with the iron hoop around it, at the corner of the Graben," replied her companion. "We will reserve that tale for the evening," answered Herr Müller; "it is getting toward coffee hour, and we want to visit many places yet." As he spoke, they walked slowly along the Graben, which means Moat in German, and, at the end of several minutes, they reached a large open square called Platz am Hof. "Here is what remains of the palace of the House of Babenberg, which Duke Heinrich built," said Herr Müller; "and here before it you see the Tiefe-graben, or deep moat, which amply protected the stronghold from attack. And there," he continued, moving as he spoke toward the building, "stands the Schottenhof." "The Schottenhof?" exclaimed Teresa, astonished. "Why is it called a Scottish palace in Austria?"