<P> In the second phase of the conflict, Timur took a different route against the enemy by invading the realm of Tokhtamysh via the Caucasus region . In 1395, Timur defeated Tokhtamysh in the Battle of the Terek River, concluding the struggle between the two monarchs . Tokhtamysh was unable to restore his power or prestige, and he was killed about a decade later in the area of present - day Tyumen . During the course of Timur's campaigns, his army destroyed Sarai, the capital of the Golden Horde, and Astrakhan, subsequently disrupting the Golden Horde's Silk Road . The Golden Horde no longer held power after their losses to Timur . </P> <P> In May 1393, Timur's army invaded the Anjudan, crippling the Ismaili village only a year after his assault on the Ismailis in Mazandaran . The village was prepared for the attack, evidenced by its fortress and system of underground tunnels . Undeterred, Timur's soldiers flooded the tunnels by cutting into a channel overhead . Timur's reasons for attacking this village are not yet well understood . However, it has been suggested that his religious persuasions and view of himself as an executor of divine will may have contributed to his motivations . The Persian historian Khwandamir explains that an Ismaili presence was growing more politically powerful in Persian Iraq . A group of locals in the region was dissatisfied with this and, Khwandamir writes, these locals assembled and brought up their complaint with Timur, possibly provoking his attack on the Ismailis there . </P> <P> In 1398, Timur invaded northern India, attacking the Delhi Sultanate ruled by Sultan Nasir - ud - Din Mahmud Shah Tughluq of the Tughlaq Dynasty . He was opposed by Ahirs and faced some reversals from the Jats, but the Sultanate at Delhi did nothing to stop him . After crossing the Indus river on 30 September 1398, he sacked Tulamba and massacred its inhabitants . Then he advanced and captured Multan by October . </P> <P> Timur crossed the Indus River at Attock (now in Pakistan) on 24 September 1398 . His invasion did not go unopposed and he encountered resistance from the Governor of Meerut during the march to Delhi . Timur was still able to continue his approach to Delhi, arriving in 1398, to fight the armies of Sultan Nasir - ud - Din Mahmud Shah Tughluq, which had already been weakened by a succession struggle within the royal family . </P>

Who was tha sultan of delhi when timur invaded the city