In the ensuing collapse and fragmentation of the empire after the capture of the Iranian capital of Isfahan by the Afghans, a claimant to the Safavid throne, Tahmasp II, accepted Nader (who was no more than a petty warlord in Khorasan) into his service.

His subsequent campaigns against the Lezgis in the northernmost reaches of the Caucasus proved to be less successful and his siege of Baghdad was lifted prematurely due to an uncharacteristic lethargy in Nader's generalship.

A courtier in Isfahan by the name of Malek Mahmoud Sistani reached an accord with the Hotaki Afghan conquerors in which he would set up an independent kingdom in Khorasan in exchange for his recognition of Mahmud as Shah of Iran.

The Qajar contingent however remained with the Loyalist army despite Fathali's beheading and ironically it was a betrayal on the other side of the conflict that brought the siege to an end where Pir Mohammad allowed Nader to infiltrate the city walls forcing Sistani to take refuge in the citadel, surrendering shortly after.

The defeated Malek Mahmoud Sistani was surprisingly treated with courtesy and in a show of reconciliatory mercy allowed to spend the rest of his life as a sage (Though he was executed the following year when he became suspect in Nader's eyes).

Nader having recently concluded a successful campaign against his own monarch and prince, the badly humiliated Tahmasp II, set out from Mashad on May 4, 1729, making sure the Shah also accompanied him on this journey where he could be kept under close supervision.

With the Abdalis in Herat brought into orbit the road now lay open to the heartland of the Iranian empire and the liberation of Isfahan seemed feasible given the successes of the previous campaigns.

At this juncture there was no realistic hope for a revival of Afghan fortunes and near Zarghan the Iranian engaged and decimated the last army Ashraf commanded, with historical sources disagreeing on his exact fate in the aftermath of the battle.

Despite support from the Turks, Nader still managed to completely destroy Ashraf's forces in numerous engagements which led to re-establishing the Safavid state under the nominal rule of Tahmasp II.

The Campaign of Tahmasp was a failed attempt to launch an offensive into Ottoman held Caucasus which ended in a disastrous defeat with all of Nader's gains during the previous year being lost.

The result of this particular military catastrophe was still overturned with Nader's return from the east but would have much more significant impact on the Safavid dynasty itself as Tahmasp II sealed his own fate by initiating this ill-fated expedition.

Nader had to cancel his planned invasion of Ottoman held Caucasus territory in light of the fact that the Abdali Afghans had rebelled and invaded Khorasan, besieging its provincial capital Mashhad.

Although Michael Axworthy and many other historians accuse Tahmasp of being motivated primarily by jealousies caused by his illustrious commander-in-chief's incessant victories there is reason to suspect his decision was in fact induced by court intrigue amongst the imperial entourage eager to have their Shah outshine Nader and thereby lessen his influence.

The conclusion of his incompetence in this foreign venture had resulted in signing one of the most humiliating treaties of his dynasty although this seemed to weigh little on his mind as he soon returned to Isfahan to resume a magnificently opulent lifestyle.

Ottoman held Iraq seemed a peculiar choice for Nader's invasion as all the western territories of Iran were restored under the ignominious treaty signed by Tahmasp with the Caucasus under Turkish control.

The mountain path was a difficult and snowy route to negotiate and some amongst the soldiers perished but Nader managed to get his 600 men to descend down into the valley behind the Ottoman battlements and without hesitation struck in the dead of night.

An intense musketry duel was kept up along the entire breadth of the line until Nader ordered his infantry unsheathe their sabres and charge the Ottomans, supporting them with a pincer movement by his cavalry reserve which put Topal Osman's army in a cauldron of Iranian troops.

Although the Abdalis had little chance of actually taking the city as what little artillery they possessed would make hardly any impression on the battlements of Mashad, these events shook Nader who received word that his power base back in Khorasan was under threat.

The negotiations lasted a long while but were eventually concluded, giving Zulfaqar Khan and his brother a chance to escape to Qandahar whilst Herat came under occupation but was surprisingly not looted or sacked by Nader's troops.

After Tahmasp Khan Jalayer engaged and routed a joint Ottoman and Crimean Tatar force in the south east Caucasus Nader cut their line of retreat further west dealing them another crippling blow, scattering them into the mountains north.

The mountains to the north in Avarestan made any pursuit of the defeated foe a daunting prospect especially considering the approach of winter, so Nader chose to turn west and besiege Ganja where he was drawn into an intense effort to capture the surprisingly formidable fortress.

The Iranian artillery was still severely lacking in strong siege guns and consisted mostly of field batteries which were effective in battles but unable to make significant impact against city walls and battlements.

Failing in their siege artillery capacity the Iranians sent sappers to dig underground to reach the citadels walls from beneath but the Turks received timely intelligence reports revealing the intention of the besiegers.

The crushing defeat at Baghavard also provided sufficient persuasion to retreat for the 50,000 Crimean Tatars who were commanded by the Turkish Sultan to march south along the coast of the Black Sea descending down into the Caucasus in order to aid Koprulu Pasha's forces.

In 1738, Nader Shah conquered Kandahar, the last outpost of the Hotaki dynasty, he, then, began to launch raids across the Hindu Kush mountains into Northern India, which, at that time, was under the rule of the Mughal Empire.

He defeated his Afghan enemies fleeing into the Hindu Kush and also seized major cities in the region such as Ghazni on May 31, Kabul on June 19, and Peshawar (November 18), before advancing onto the Punjab and capturing Lahore.

The majority of the Iranian casualties were from the extremity of the weather as well as the outbreak of disease, all of which combined with the indomitable will of the Dagestan people to wage an insurgency and retreat to their distant strongholds when threatened with a pitched battle made the entire war a quagmire for Nader's forces.

Ultimately the Dagestan people who had held on in the northern fortresses marched south upon hearing of Nader's assassination and reclaimed most of their lost territories as the Iranian empire crumbled.

The numerous campaigns that were undertaken were initially very successful and achieved a great many objectives however the rebellion of Nader's appointed Darya Salar (Admiral), Mohammad Taqi Khan, wreaked havoc amongst the plethora of polities across the Persian gulf that had been brought under Iranian control and even after the defeat and capture of Mohammad Taqi Khan the Iranian empire was going through a tumultuous period of unrelenting civil strife and internal war due to Nader's increasingly brutal rule which made the empire collapse in the immediate aftermath of his assassination, leading to many of the conquests in the region to be lost.

Therefore, he raised an army of 200,000, which consisted largely of rebellious Central Asian tribesmen, and he planned to march towards Constantinople, but after he learned that the Ottoman ulema was preparing for a holy war against Iran, he turned eastward.