"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[14] 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,[15] 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,