Initial administrative actions Immediately after accession to the throne, Husain Shah ordered his soldiers to refrain from plundering
Gaur, his capital city. But being annoyed with their continuous plundering, he executed twelve thousand soldiers and recovered the looted articles, which included 13,000 gold plates. Subsequently, he disbanded the
paiks (the palace guards) who were the most significant agitators inside the palace. He removed all
Habshis from administrative posts and replaced them with
Turks, Arabs,
Afghans, and
Bengalis.
Engagement with the Delhi Sultanate Sultan
Hussain Shah Sharqi, after being defeated by
Bahlol Lodi, retired to Bihar, where his occupation was confined to a small territory. In 1494, he was again defeated by Sultan
Sikandar Lodi and fled to Bengal, where he was granted asylum by Sultan Ala-ud-Din Husain Shah. This resulted in an expedition against Bengal in 1496 by Sultan Sikandar Lodi. Husain Shah of Bengal sent an army under his son
Shahzada Danyal to fight with the Delhi army. The armies of Delhi and Bengal met at
Barh near
Patna. The Delhi army suffered from logistics problems from the beginning of the campaign, and thus Sikandar Lodi halted the advance of his army and concluded a treaty of friendship with Ala-ud-din Husain Shah. According to this agreement, the country west of Barh went to Sikandar Lodi while the country east of Barh remained under Husain Shah of Bengal. The final dissolution of the Jaunpur Sultanate resulted in the influx of the Jaunpur soldiery in the Bengal army, which was further strengthened by it. Moreover, the Lodis could not maintain their dominance over the entirety of the Jaunpuri territory they annexed, leading to Bengali expansion in Uttar Pradesh. This is signified by Alauddin Hussain Shah's numerous inscriptions that record the construction of mosques: a Jama Mosque in Kharid village of Balia district of Uttar Pradesh, another mosque in Sikdarpur, Azamgarh district, Uttar Pradesh, and another mosque in Hussainabad of Balia district in 1501-02, Hussainabad being named after Husain Shah himself. This indicates firm control of Husain Shah in trans-Gandak area of Uttar Pradesh.
Conquest of Kamrup-Kamatapur was thought to have been built by Husain Shah to commemorate the Kamata victory.Nilambar, the Khen dynasty ruler of
Kamata Kingdom, had expanded his territory up to Kamrup on the bank of the river Baranadi in the east, and river Karatoya in Bengal in the south. Taking advantage of the Abyssinian anarchy in Bengal, he consolidated his territory by constructing a road from his capital to Ghoraghat in Dinajpur. In response, in 1498, Alauddin Husain Shah prepared to invade Kamatapur. His campaign was aided by the defection of a minister of King Nilambar. In 1499, Husain Shah invaded Kamatapur with his army, which reportedly consisted of 24,000 infantry, cavalry and a war flotilla. Nilambar had taken strong defensive measures in his capital of Kamatapur, and constructed a string of forts across his kingdom, including forts in
Sadullapur,
Ulipur and
Jaldhaka. Husain's army started marching towards Kamatapur by taking fort Fatehpur in Sadullapur, while the navy started from Ekdala. Husain Shah personally defeated the combined army of local kings Rupnarayan, Manakumar, Lakshmana and Lakshmimana, whereas Husain Shah's general,
Shah Ismail Ghazi, marched straight to Nilambar's capital. After a long siege, Ismail defeated and imprisoned King Nilambar of Kamata, pillaged and destroyed the capital city and annexed the territory of Kamatapur and Kamrup up to
Hajo, 16 miles from Guwahati, the capital of Assam. A colony of Afghans was left behind at Hajo to set up administration, and prince
Danyal was appointed viceregent of Kamatapur. The victory was publicly recorded in an inscription at
Malda.
Odisha campaign According to the
Madala Panji,
Shah Ismail Ghazi commenced his campaign from the
Mandaran fort (in the present-day
Hooghly district) in 1508-09 and reached Puri, raiding Jajpur and
Katak on the way. The Gajapati King of Orissa,
Prataparudra Deva was busy in a campaign in the south. On hearing the news, he returned and defeated the invading Bengal army and chased it into the borders of Bengal. He reached the Mandaran fort and besieged it, where the general had taken shelter. The general managed to escape along with some of his soldiers. Rest of the forces of Bengal were routed, and the fort was besieged by Prataparudra's army. However, due to the treachery of one of Prataprudra's officers, the siege had to be raised and the Orissan soldiers withdrawn. Intermittent hostilities between the Bengal and Orissa armies along the border continued throughout the reign of Husain Shah, and by 1515 Orissa was a vassal of Bengal Sultanate.
Expansion in the Northeast When Gouhar Khan, the Bengali governor of
Sylhet (in present-day
Bangladesh) died, the district was seized by ruler of the neighbouring kingdom of
Pratapgarh, Sultan Bazid. One of Husain Shah's nobles named Surwar Khan was sent to confront Bazid and when attempts at negotiations failed, fought against the Sultan and his allies. Bazid was defeated and captured and was forced to give heavy concessions to keep his kingdom, though under the suzerainty of Bengal. In reward for his actions, Surwar Khan was named the new governor of Sylhet and the defeated Sultan's daughter was given in marriage to his son, Mir Khan. In the northeast Husain Shah extended the boundary of his sultanate beyond Karimganj, up to Kachar district of Assam. This is signified by a inscription found in a mosque built in Kaliganj Bazar, Kachar in 1503-1504 by Sher Malik, the son of Malik Sadami the Magh, which mentions Husain Shah as the ruling sovereign. In 1513, Husain's governor in Sylhet, Rukn Khan, defeated eight tribal chiefs ruling in the borders of Sylhet.
Expeditions to Tripura and Arakan According to
Rajmala, a late royal chronicle of
Tripura, Husain Shah despatched his army four times to Tripura. The Tripura army offered stiff resistance and did not yield any territory, but in the fourth expedition Hussain Shah succeeded to annex at least some portion of the territory of Tripura. The 1513 Sonargaon inscription of Khawas Khan, entitled
Sar-i-Lashkar-i-Tripura (Commander-in-chief of the Army Stationed in Tripura) is interpreted by a number of modern scholars as an evidence of annexure of at least a part of Tripura by Husain Shah. During Alauddin Husain Shah's expeditions to Tripura, the ruler of Arakan helped Dhanya Manikya, the ruler of Tripura and expelled Husain Shah's officers from Chittagong. In 1516, Husain Shah decided to launch an expedition to Arakan. Husain assigned the charge of the land army for Arakan expedition to Paragal Khan; prince Nasrat, who was made crown prince of Bengal in 1515, was placed in overall command. On Nasrat's order, Paragal Khan advanced from his base on the Feni River. The territory up to the western bank of Kaladan river was placed under his governorship administration. The hostilities probably ended in 1516, when Mrauk U recognized Bengali sovereignty over Chittagong and northern
Arakan. Husain Shahi victory over Arakan is also corroborated by Portuguese adventurer Joao de Silvera who, landing in Chittagong in 1517, stated that Arakan was a vassal state of Bengal Sultanate. The Portuguese explorer,
Vasco da Gama, arrived India by sea in 1498. Consequently, a Portuguese mission came to Bengal to establish diplomatic relations towards the end of Husain Shah's reign. Husain Shah's long reign of more than a quarter of a century was a period of peace and prosperity, which was strikingly contrast to the period that preceded it. The liberal attitude of Husain Shah towards his Hindu subjects is also an important feature of his reign. Many
Brahmins had taken service at his court. ==Cultural contribution==