Joining a large band of Assiniboins, he pushed southwest across the prairie and reached a Mandan village probably somewhere near the modern New Town, North Dakota, about 70 miles east of the Montana border. He did not push on to the Missouri River, but sent his son Louis-Joseph to do it for him. In order to get rid of their numerous Assiniboine guests, the Mandan claimed that there was a Sioux war party in the area. The Assiniboines fled, taking with them the Cree interpreter. Unable to talk to the Mandan, La Vérendrye left two Frenchmen to learn the language and returned to Fort La Reine (January 1739).