Ahom–Mughal wars (January 1615 – August 1682)[2] refers to the series of 17th-century conflicts between the Ahoms and the Mughals over the control of the Brahmaputra valley.

The Mughals since then maintained interest in the region west of the Manas River via zamindars, till they were ousted from Bengal by the British about a hundred years later.

As the kingdom pushed west it came under attack from Turkic and Afghan rulers; and on one occasion the Ahoms general Ton Kham Borgohain pursued retreating invaders through a nascent Koch kingdom and reached the Karatoya river —and since then they began to see themselves as the rightful heir of the erstwhile Kamarupa kingdom From the beginning the relationship between the Ahoms and the Mughals was hostile and that was due to certain factors, such as, the Mughal alliance with Koch Bihar, the western enemy of the Ahoms and secondly the growing advance of the Mughals in their north-eastern frontier which alarmed them.

While the Mughals supported Lakshminarayan, son of Nara Narayan of Koch Behar, the Ahom king Sukhaamphaa (1552–1603) entered into alliance by marrying the daughter of Lakshminarayan's cousin Raghudeva, the son of Chilarai who became the ruler of the eastern part of the kingdom, Koch Hajo, which approximately included the modern districts of Goalpara, Barpeta, Kamrup, Darrang, and a part of Sonitpur (up to Bharali).

But unfortunately, in spite of being pacified, Raghudeva and his successors remained all along hostile towards the Koch royal house and this rivalry and antagonism between these two frontier states invited intervention and aggression of their two mighty neighbourhood powers: the Mughals on the west and Ahoms on the east.

After the extinction of the Kamrup monarchy, the Mughals came to regard the territory east of Barnadi up to Singiri as part of the conquered region and hence asserted their political right over it.

The Mughals got the necessary pretext for war and an imperial army was at once dispatched in 1615 under the command of Abu Bakr and Raja Satrajit of Bhusna.

The imperial army advanced towards Barnagar, the old capital of Kamrup and next moved to Hajo and numerous outposts were raised in the surrounding region.

The first was the asylum given by the Ahom king to the hill-chiefs of Dhanikal who had sought his protection against the ill-treatment of the Bengal Subahdar Qasim Khan Chishti.

The second factor, which precipitated the crisis, was the wickedness and treachery of Satrajit, the Thanadar of Pandu who made a common cause with Balinarayan and instigated him to take advantage of the change of governor in Bengal in order to attack Kamrup.

Although the faint-hearted Ahom admiral retired from the battlefield, the garrison in the fort of Samdhara offered such a gallant defence that the Mughals had to give up the contest with great loss of men and materials.

But, Jayadhwaj Singha (1648–1663), taking advantage of the emperor Shah Jahan's illness and the war of succession, expelled the Mughals from Gauhati, and chased them down beyond the river Manaha (Manas).

But, King Jayadhwaj Singha had appointed a Kayastha as viceroy of Western Assam and commander-in-chief of the Ahom army despatched against Mir Jumla leading to resentment among the ranks.

Mir Jumla's march into Assam was an uninterrupted series of triumph and victories through the real secret of his success, namely, defection in Ahom camp, which has not been touched upon by any historian of the expedition.

At last a treaty was concluded at Ghilajharighat in January 1663, according to which the Ahoms ceded western Assam to the Mughals and promised a war indemnity of three lakhs of rupees and ninety elephants.

Thus, according to the treaty Jayadhwaj Singha transferred Kamrup to the possession of the Mughals and promised to pay a heavy war indemnity.

In 1665 the king summoned an assembly of his ministers and nobles and ordered them to adopt measures for expelling the Mughals from western Assam, adding—"My ancestors were never subordinate to any other people; and I for myself cannot remain under the vassalage of any foreign power.

"[17][18] A large portion of the war indemnity still remained undelivered for which the Ahom king had to receive threatening letters from Syed Firoz Khan, the new Faujdar at Guwahati.

Sayed Firoj Khan, the imperial governor of Guwahati and his army were not prepared for such an eventuality, with the result that the Ahoms gained a series of victories over the enemy.

The Ahom also succeeded in bringing back the Assamese subjects who had previously been taken as captives by the Mughals during the expedition of Mir Jumla.

The success of the Ahoms in recovering possession of Guwahati and western Assam forms a momentous chapter in the history of their conflicts with the Mughals.

He commissioned Raja Ramsingh I of Amber, son of the distinguished general Mirza-Raja Jai Singh I, to lead an invasion of Assam.

On Ram Singha's arrival at Rangamati, the Ahom commanders stationed at Manaha attempted to oppose the advance of the enemy.

Lachit Borphukan, the commander-in-chief of the Ahom camp, had realized fully that postponement of the open encounter would enable him to bring his preparations to perfection in the light of the enemy's superior strength.

Firoz Khan, ex-Fauzadar of Guwahatii, now a prisoner of the Ahoms, was released and Lachit Barphukan sent him to Raja Ram Singh with the above message.

[30][31] Battle of Alaboi, At this juncture, Ramsingh I challenged Swargadeo Chakradhwaj Singha to single combat, and undertook, if he were defeated, to return with the army to Bengal.

They followed up this success by taking the fort at Agiathuti, but soon afterwards Ram Singha attacked the Ahom army and routed it, inflicting heavy loss.

[33][34] In the meantime Ramsingh I sent a letter to the Barphukan inviting the king of Assam to fight a duel in the presence of the two hostile armies.

But the Ahom king dismissed the insolent challenge by simply saying—"Ram Singha is a mere servant and he has no umbrella over his head.

Thus Ahoms remained in undisturbed possession of their territories till 1679 A.D.[40] In 1679, during the reign of Sudoiphaa or Parvatiya Raja,[41] Laluk Barphukan, the Ahom viceroy of Gauhati, and his brother entered into a conspiracy and invited Muhammad Azam Shah, the then Nawab of Bengal (married to his niece Ramani Gabharu), to take possession of the fort at Saraighat.