Crossing the Euphrates and Tigris Rivers

River crossings are generally considered mere accessory events in Alexander's campaign, but they are widely underestimated. On their way east, the Macedonians had to cross countless rivers, streams, and rivulets. Each of these, however, came with its own challenges: some were mere sandy flats while others were filled with rocks; some banks were steep and slippery while others were marshy and swampy; some streams were lazy water ribbons while others were torrential white waters; and some were hazardous while others were placid.

Over the years, Alexander crossed many significant rivers, among which the most important are the Danube, the Nile, the Euphrates and the Tigris, the Oxus and the Jaxartes, and finally, the Indus, including the entire Punjab, i.e., the Hydaspes (Jhelum), the Acesines (Chenab), the Hydraotes (Ravi), and the Hyphasis (Beas). This time, let us concentrate on the Euphrates and the Tigris, major barriers to Alexander's march through Mesopotamia.

In mid-July 331 BC, Alexander sent Hephaistion ahead to build two bridges over the Euphrates. Such crossing points were well-known in antiquity, and Alexander's intelligence must have provided the necessary information. The most amazing part of such expeditions is the logistics involved. It is said that Alexander transported his ships in separate elements from Phoenicia to be reassembled on the banks of the Euphrates. Even in a straight line from the eastern Mediterranean, let's say from Antioch-on-the-Orontes (Antakya) to Thapsacus (Carchemish), we are talking about a distance of more than 200 km, implying that he must have planned this colossal move early on, maybe even while he was still at Tyre. As always, his invaluable scouts did a thorough reconnaissance job, for Alexander could not take chances to expose Hephaistion and his advanced forces to enemy attacks on the way. Even more admirable is the timing of the entire operation since the bridges had to be completed by the time Alexander and the bulk of his army arrived. 

Hephaistion's forces included carpenters and engineers who directed the hauling of the ship's parts, but also enough soldiers to do the foraging and to withstand any unexpected attack by local tribes or those people still faithful to the Persians. The crossing point was near Thapsacus, where the river was about 800 meters wide. Unfortunately, the river banks are now flooded by yet another dam further upstream, and archaeologists can't investigate this in any way. 

Meanwhile, King Darius knew that Alexander had to cross the river. He sent his most experienced general, Mazaeus, with instructions to burn the crops ahead of the enemy route. Although the harvest had already taken place, this order was carried out, and little was left to burn. Besides, this policy had no effect since Alexander took a more northerly route which Darius had not expected.

We know that Mazaeus arrived on the eastern bank of the Euphrates and watched Hephaistion's construction progress for several days. Hephaistion stopped his operation short of the opposite river bank to avoid seeing the end of his bridges destroyed by Mazaeus. There was little else to do for Mazaeus but to wait, but when Alexander appeared with the bulk of his army, he turned around and left to further execute his orders of scorching the earth.

By now, it must have been mid-August, and soon the two bridges were completed. This means that Hephaistion accomplished his task in a maximum of six weeks times – speaking of engineering prowess! Of course, these were no bridges in the true sense of the word but boats and rafts tied together with ropes and chains. A walkway of planks was placed over the boats, and the passage was created to move the nearly 50,000 troops across, as well as the thousands of horses. It seems it took the army five days to cross the Euphrates.

Alexander led his troops further east, and on the road, he learned from spies that Darius was encamped on the Tigris River. As an army is most vulnerable when crossing a river, Alexander force-marched his troops and reached the Tigris two weeks later. Here he found no sign of Darius and nobody to stop his army. The obvious fording location has been pinned at Abu Dhahir, near the Persian Royal Road.

There was no need to build a floating bridge over the Tigris River since its waters were shallow, although fast-flowing and men could simply wade through. Well, this is the simple version that most historians like us to believe, but Diodorus tells an entirely different story. According to him, Mazaeus had decided that the river could not be crossed at the time because it ran too deep and its current was too swift. Consequently, the Persian general did not find it necessary to guard the crossing. So, when Alexander arrived at the ford, the water was above a man's breast, and the current swept away those who entered the river. At this stage, Alexander ordered all his men to lock arms with each other and "to construct a sort of bridge out of the compact union of their persons."

Yet the most vivid and perilous report is given by Curtius. He mentions that Alexander cautiously sent a few of his cavalry to test the river. The water rose up to their horses' flanks and when they were mid-channel to their necks. "Tigris" in Persian means "arrow," and the river owes its name to its current running as fast as an arrow. Alexander ordered his troops in formation with the infantry in the center. The men had to carry their weapons above their heads as they waded through the river with great difficulty. Like in a battle formation, the cavalry was posted on either side where the horses upstream would break the strong current, and the cavalrymen downstream would catch those soldiers who lost footage and were swept away. Alexander directed the operation like on a battlefield, pointing his troops in this or that direction and encouraging them to move on. They all landed safely without any loss of life, only some material losses.

Once one dry land, Alexander gave his men a well-deserved rest. This was at the time of the moon eclipse that occurred on 20 September, and it has been recorded that Alexander sacrificed to the Sun, the Moon, and the Earth.

[Bottom picture is from World Archaeology]