In the negotiations following the catastrophic defeat, Muhammad Shah agreed to pay a large indemnity in exchange for maintaining his imperium over his lands.

[13] A popular destination for the plethora of Afghan mercenaries and warlords who were defeated in Nader's numerous campaigns against the various polities in Afghanistan was the northern border areas of the Mughal Empire.

He seized upon that opportunity to mask his invasion in the form of a hunt for the Afghan warriors who had found asylum in the rugged terrain of the northern Mughal realm.

[2][3] Hearing of Nader Shah's approach from Qandahar, the governor of Peshawar and Kabul raised an army of 20,000 men, mostly of Afghan mercenaries drawn from the tribes of eastern Afghanistan to check the Persian advance.

The position that had been chosen to resist the Persian army could scarcely have been better selected, as through the narrow Khyber Pass, only a small column of men could hope to march and any deployment into fighting formations would be an impossibility.

[citation needed] Setting out on 26 November from near Jalal Abad, the Persian army arrived at Barikab (33 kilometres from the Kheibar pass) where Nader divided his army, leaving Morteza Mirza behind with the bulk of the forces at his disposal and sending forth 12,000 men to the Khyber Pass under Nasrollah Qoli while he gathered 10,000 chosen light cavalry under his direct command.

Beginning an epic flank-march of over 80 kilometres through some of the most unnavigable terrain in Asia Nader reached Ali-Masjed whence the 10,000 curved their route of march northwards and onto the eastern end of the Kheibar pass.

[citation needed] The news of the series of conquests by Nader's invading army had caused much consternation at the Mughal court of Muhammad Shah residing in Delhi.

Due to the cumbersome size of the Mughal army, Muhammad Shah could not take his forces any further than Karnal, approximately 120 kilometres north of Delhi.

Almost all of the guns in the army were far too large in calibre to be considered field artillery as they were practically impossible to manoeuvre during battle and took such a long time to reload that they would have minimal effect even in cases of correct utilisation.

Although the 50,000 cavalry contingent in the Mughal army was of excellent quality, there was nothing to suggest a common and cohesive underlying military structure set out for their deployment and use.

Nader began devising a stratagem based around using Sa'adat Khan's approach to lure the main Mughal army across Alimardan river and into the valley before Kanjpura village where he intended to give battle from an advantageous position.

The long-awaited Sa'adat Khan entered the Mughal encampment to much jubilation; however, the bulk of his column (some twenty or thirty thousand soldiers) was still en route.

The centre of the army was positioned just north of the village of Kanjpura facing west and commanded by Nader's son, Morteza Mirza (who would later be renamed Nassrollah Qoli in honour of his achievements in the coming battle), with a retinue of senior advisers at his disposal.

[citation needed] At this juncture, news was brought to Sa'adat Khan that the rearguard of his column had come under attack, and 500 richly laden camels from his baggage train had been captured and carried off by the enemy.

Although Sa'adat Khan had managed to reach the Mughal camp late the previous night, a large portion of his forces, some twenty or thirty thousand men, were still en route at the time of his arrival.

[27] Without consulting or convening either Muhammad Shah or other commanders, Sa'adat Khan immediately mounted his war elephant and rode out to the reported site of the skirmish.

Sa'adat Khan engaged the isolated Persian cavalry units deployed in the vicinity of the area, which made a show of resistance before feigning a rout towards the east.

Sending urgent reports back to camp of the upper hand he had gained, Sa'adat Khan pleaded for reinforcements in order to complete the victory.

A frustrated Muhammad Shah made insinuations regarding the martial character of Khan Dowran, to which he responded zealously by donning armour and mounting his war elephant in preparation for battle.

This ambushing force consisted of three one thousand strong units of dismounted cavalry from the Qajar, Bakhtiari and Kurdish tribes, waiting behind the village's walls with their heavy jazāyer muskets.

[9] Further to the south, where the Persian left flank was positioned at Kanjpura, Khan Dowran played right into Nader's hands as his pursuit suddenly marched right into a bloody ambush.

The sheer volume of fire from the jazāyers and zamburaks raked incredible destruction on the unfortunate Mughal soldiers caught in the bewildering mayhem Nader had concocted.

The cavalry of Khan Dowran, consisting of Indian Muslims,[31] looked down on fighting with muskets with contempt, which was a talent of the mostly Hindu infantrymen in India.

[citation needed] Although the meeting was initially tense, with the Mughal plenipotentiaries arriving with armour instead of plain clothing, Nader soon requested that he and Nizam-ul-Mulk be left alone to discuss matters more freely.

After Sa'adat Khan's humiliating defeat at Karnal, his open disloyalty to his emperor in the aftermath, his ignominious failure to curry favour with the person he believed was his new patron, forced to rob his own people of their wealth for a foreign invading host, he became burdened to such an extent that he died in Delhi no more than just a few days after his arrival in that city.

[citation needed] Persian troops left Delhi at the beginning of May 1739, also taking with them thousands of elephants, horses, and camels, all loaded with the booty they had collected.

Khodayar Khan believed that Nader would not traverse the punishingly rugged terrain of the Hindu Kush mountains so late into the campaigning season.

[citation needed] The Maathir-ul-Umara states that Khudayar Khan answered:[52] "We from the time of our forefathers were the servants of the King of India, if we had shown an inclination for you, you would not have believed us."

Nader Shah's victory against the crumbling Mughal Empire in the East meant that he could afford to turn to the West and face Persia's archrivals, the Ottomans, once again.