Josephus gives an admirable account from personal knowledge of balistas and catapults in warfare, especially of their effects at the siege of Jotapata, A.D. 67, and at that of Jerusalem, A.D. 70. See pp. 267, 268.

Caesar, Marcellinus, Plutarch and Tacitus also more or less fully describe these engines and the destruction they caused.

Among later writers, Pere Daniel and Grose treat siege engines in considerable detail ; Grose giving many drawings of balistas and catapults.

Viollet-le-Duc in his exhaustive work on military architecture has several excellent illustrations of ancient siege engines, derived like those of Grose from the books and manuscripts of mediaeval authors.

The late Emperor of the French, Napoleon III, was much interested in historic weapons. In an elaborate book he ordered to be compiled on military arms ancient and modern, entitled ' Etudes sur l'artillerie,' there are plans of the full-sized balista and trebuchet which he caused to be made, and with which many experiments were carried out in Paris to ascertain what were the effects of similar engines in ancient and mediaeval warfare.

Some years ago these models were to be seen in the museum of Roman antiquities at Saint Germain-en-Laye, but I do not know if they are there now.

The largest siege engines used in ancient times were so ponderous that it was often impossible to transport them overland in bulk. For this reason, unless carriage by water was available, the principal parts of such an engine, as its winches, windlasses and cordage, were usually carted separately to the vicinity of the town about to be besieged. Its wooden framework was then made on the spot from trees cut down in the neighbourhood.

In some cases we read that the huge logs of wood which formed the frame of a heavy engine were dragged independently by oxen to the scene of attack and there fitted together.