came to invite the Russian princes to the khan's court for the confirmation of their diplomas of investiture, he was faced with so much hostility by the population, that he turned back after reaching Nižnij Novgorod. Tokhtamysh prepared for war in 1382. Intending to catch his enemy by surprise, he began by ordering the arrest and robbing of Russian merchants on the Volga and the confiscation of their boats. Crossing the river with his entire army, he attempted to advance secretly, but attracted much attention. Seeking to ingratiate himself with the khan, Grand Prince Oleg Ivanovič of Rjazan' placed himself at the khan's disposal, pointing out the fords over the Oka river; Grand Prince Dmitrij Konstantinovič of Nižnij Novgorod also submitted readily and sent his sons Vasilij and Semën to join Tokhtamysh's campaign as guides. Grand Prince Dmitrij of Moscow did not submit, but left a strong garrison in his capital under the Lithuanian prince Ostej and sought out the greater safety of Kostroma, from where he hoped to gather greater forces. After taking Serpukhov, Tokhtamysh's forces reached and besieged Moscow on 23 August 1382. Three days later, the citizens were tricked into surrendering by Vasilij and Semën of Nižnij Novgorod, and Tokhtamysh's troops stormed into the city, slaughtering, plundering and finally razing it for the insubordination of its ruler. Other cities taken by the Mongols during the campaign included Vladimir, Zvenigorod, Jur'ev, Perejaslavl'-Zalesskij, Dmitrov, Kolomna, and Možajsk. On his way back, Tokhtamysh also sacked Rjazan', despite the cooperation of its prince. Later relations with the Russian principalities After the submission of the Russian princes and the resumption of their tribute, Tokhtamysh adopted more conciliatory policies toward them. Dmitrij of Moscow razed Rjazan' in vengeance for Oleg Ivanovič's collaboration with Tokhtamysh against Moscow, but suffered no punishment for it. Mihail Aleksandrovič of Tver' was invested as Grand Prince of Vladimir and visited Tokhtamysh's court with his son Aleksandr, but never succeeded in entering into possession of the Grand Principality, as Tokhtamysh soon forgave Dmitrij of Moscow. Dmitrij had submitted, surrendered his eldest son Vasilij Dmitrievič as hostage, and promised to pay tribute, duly dispatched in 1383. When Dmitrij Konstantinovič of Nižnij Novgorod died the same year, Tokhtamysh granted that principality to his brother Boris Konstantinovič, but gave Suzdal' to Dmitrij's sons Semën and Vasilij. In 1386, Dmitrij of Moscow's son Vasilij, hostage at Tokhtamysh's court, escaped to Moldavia and made