Turning west again, Thutmose took Simyra and quelled a rebellion in Ardata, which apparently had rebelled again. To stop such rebellions, Thutmose began taking hostages from the cities in Syria. The cities in Syria were not guided by the popular sentiment of the people so much as they were by the small number of nobles who were aligned to Mitanni: a king and a small number of foreign Maryannu. Thutmose III found that by taking family members of these key people to Egypt as hostages, he could drastically increase their loyalty to him. Syria rebelled again in Thutmose's 31st year and he returned to Syria for his seventh campaign, took the port city of Ullaza and the smaller Phoenician ports and took more measures to prevent further rebellions. All the excess grain which was produced in Syria was stored in the harbors he had recently conquered and was used for the support of the military and civilian Egyptian presence ruling Syria. This left the cities in Syria desperately impoverished. With their economies in ruins, they had no means of funding a rebellion. After Thutmose III had taken control of the Syrian cities, the obvious target for his eighth campaign was the state of Mitanni, a Hurrian country with an Indo-Aryan ruling class. However, to reach Mitanni, he had to cross the Euphrates River. He sailed directly to Byblos and made boats which he took with him over land on what appeared to otherwise be just another tour of Syria, and he proceeded with the usual raiding and pillaging as he moved north through the lands he had already taken. He continued north through the territory belonging to the still unconquered cities of Aleppo and Carchemish and quickly crossed the Euphrates in his boats, taking the Mitannian king entirely by surprise. It appears that Mitanni was not expecting an invasion, so they had no army of any kind ready to defend against Thutmose, although their ships on the Euphrates did try to defend against the Egyptian crossing. Thutmose III then went freely from city to city and pillaged them while the nobles hid in caves, or at least this is the typically ignoble way Egyptian records chose to record it. During this period of no opposition, Thutmose put up a second stele commemorating his crossing of the Euphrates next to the stele his grandfather, Thutmose I, had put up several decades earlier. A militia was raised to fight the invaders, but it fared very poorly.