CZASLAU, or Caslau, a town of Bohemia, the chief place of the circle of the same name, situated near the left bank of an affluent of the Elbe, in a fertile plain 48 miles E.S.E. of Prague, on the North-west Railway from Vienna. The church is surmounted by a lofty spire, the highest in Bohemia, and contains the tomb of the celebrated Hussite leader Ziska, who died in 1424. Here (or more accurately at the village of Chotusitz, 2∣ miles north of this) Frederick the Great defeated the Austrians, May 17, 1742. Population in 1869, 5998, chiefly agriculturists.