The Tigris can also claim, in common with the Euphrates, an interesting connection with some of the ancient kingdoms of the world, extending back to early post-diluvian times. Near by, the Assyrian Empire built its towns of splendour and strength. Daniel records visions seen upon its banks, Cyrus is said to have marched his troops along its shores, Alexander overthrew the armies of the Medes and Persians near its basin, while in the plain of Nineveh the dynasty of the Ommiade caliphs was destroyed and supplanted by that of the Abassides. The origin of its name is unknown, but it is thought that the swiftly-flowing character of the river gave rise to its name. Hence the old Scriptural name Hiddekel, signifying "swift or quick." Owing to its wealth of fertilising power, it is sometimes called by the Arabs "Nahar-as-Salam," the River of Peace. At all times the Tigris is a swift river, but the velocity with which it travels differs according to the season of the year, the swiftest time of all being in the spring, when the snows from all the surrounding mountains melt and rush down to the river, causing it often to overflow its banks, and increasing its impetuosity to a great extent. At this time it is possible to travel on the river from Mosul to Baghdad in forty-eight hours, while in the late summer or autumn it takes at least ten or twelve days. When flowing at its fastest rate, the Tigris is said to be swifter than the Danube. The course of the river is a very winding one, extending for about 1040 miles. Its breadth varies very much. At Mosul it is a little less than 400 feet, at Baghdad about 600, while in one place where another river flows into it, the width amounts to over 1000 feet. The sources of the Tigris are at an altitude about 5000 feet above sea-level, but the greater part of its fall is accomplished at its commencement, by the time it reaches Mosul the elevation above sea-level is only 353 feet, the remainder of its course, a distance of about 650 miles, being made by easy descent.