The Persians [he writes], through fear of incursions from without and for the purpose of preventing vessels from ascending these rivers, constructed artificial cataracts. Alexander on arriving there destroyed as many of them as he could, those particularly on the Tigris from the sea to Opis.[401] [He declared that] such devices were unbecoming to men who are victorious in battle and, therefore, he considered this means of safety unsuitable for him and, by easily demolishing the laborious work of the Persians, he proved in fact that what they thought a protection was unworthy of the name.[402] A short distance below Assur we passed the embouchure of the little Zab whose clear mountain waters were in strong contrast with the flood of the turbid Tigris. Near the confluence of these two rivers were located the Median villages of Parysatis, the wife of Darius and mother of Cyrus the Younger. These villages had, according to a Persian custom, been bestowed upon the queen by the king for her girdle--that is for the purchase of personal apparel and ornaments. How generous the Persian monarchs were in supplying their wives with pin money! The scenery below the Little Zab differed but little from that round about Assur--an arid plain on the left and a low range of yellow hills on the right. The Arabs call them mountains--Jebel Hamrin and Jebel Makhul--but they scarcely deserve such an exalted appellation. In a recess of Jebel Makhul are the remains of a stronghold that reminds one of similar ruins along the Danube. It is called Kalat Makhul--the Castle of the Maiden. According to an Arabian legend, this was the citadel of the warlike daughter of a giant, who was the terror of all who sailed down the river. Near by was the citadel--Kalat el Gebbar--of her giant father. The legend apparently recalls the time when these strongholds were occupied by bandits who, like the old robber barons of the Rhine and the Danube, formerly levied tribute on all the passing keleks or who despoiled their owners of all they possessed. These brigands are said to have infested certain reaches of the Tigris as late as a third of a century ago, but, although the traveler is still warned against them, they seem to have changed their scene of operations to fields where they would not be so much harassed by government soldiery. A few miles below the Giant’s Castle, the river becomes much narrower and swifter, for it here cuts through the sandstone chain of hills called Jebel Hamrin which, on the left bank of the Tigris, continues in a southeasterly direction until it unites with the one of the rugged spurs which juts out from the mountains of Luristan. This narrow section of the river through the range of Jebel Hamrin, which is locally known as El Fatha--the aperture--is interesting because it is on the boundary between the vilayets of Mosul and Bagdad, and because it once marked a point on the natural frontier between Assyria and Babylonia.