Fall of the flag discouraged the Hindus. Muslims fought over boldly entered over the fort and captured the city. Raja Dahir fled away from the battle field and was killed later.
Raja Dahar (Sindhi: راجا ڏاھر; Sanskrit: राजा दाहिर, IAST: Rājā Dāhir; 663 – 712 CE) was the last Hindu ruler of the Brahmin Dynasty of Sindh (present-day Pakistan). In 711 CE, his kingdom was conquered by the Ummayad Caliphate led by General Muhammad bin Qasim. He was killed at the Battle of Aror at the banks of the Indus River, near modern-day Nawabshah.
Reign in the Chach Nama
The Chach Nama is the oldest chronicles of the Arab conquest of Sindh. It was translated in Persian by an Arab Muhammad Ali bin Hamid bin Abu Bakr Kufi in 1216 CE from an earlier Arabic text believed to have been written by the Thaqafi family (relatives of Mukhtar al-Thaqafi).
Dahir's kingdom was invaded by King Ramal of Kannauj. According to legend Raja Dahir granted refuge to a Muslim Muhammad Haris Allafi, who killed the governor of Makran. He also fought for Dahir during attack over Sindh by ruler of Kannauj in 687 CE.
War with the Umayyads
"I am going to meet the Arabs in the open battle, and fight them as best as I can. If I crush them, my kingdom will then be put on a firm footing. But if I am killed honourably, the event will be recorded in the books of Arabia and India, and will be talked about by great men. It will be heard by other kings in the world, and it will be said that Raja Dahir of Sindh sacrificed his precious life for the sake of his country, in fighting with the enemy
The primary reason cited in the Chach Nama for the expedition by the governor of Basra, Al-Hajjaj ibn Yusuf, against Raja Dahir, was a pirate raid off the coast of Debal resulting in gifts to the caliph from the king of Serendib (modern Sri Lanka) being stolen. Meds (a tribe of Scythians living in Sindh) also known as Bawarij had pirated upon Sassanid shipping in the past, from the mouth of the Tigris to the Sri Lankan coast, in their bawarij and now were able to prey on Arab shipping from their bases at Kutch, Debal and Kathiawar.
Hajaj's next campaign was launched under the aegis of Muhammad bin Qasim. In 711 bin Qasim attacked at Debal and, on orders of Al-Hajjaj, freed the earlier captives and prisoners from the previous (failed) campaign. Other than this instance, the policy was generally one of enlisting and co-opting support from defectors and defeated lords and forces. From Debal Hajaj moved on to Nerun for supplies; the city's Buddhist governor had acknowledged it as a tributary of the Caliphate after the first campaign, and capitulated to the second. Qasim's armies then captured Siwistan (Sehwan) received allegiance from several tribal chiefs and secured the surrounding regions. His combined forces captured the fort at Sisam, and secured the region west of the Indus River.
By enlisting the support of local tribes Jats, Meds, Bhuttos, and Buddhist Jat rulers of Nerun, Bajhra, Kaka Kolak and Siwistan as infantry to his predominantly-mounted army, Muhammad bin Qasim defeated Dahir and captured his eastern territories for the Umayyad Caliphate
Sometime before the final battle, Dahar's vizier approached him and suggested that Dahar should take refuge with one of the friendly kings of India. "You should say to them, 'I am a wall between you and the Arab army. If I fall, nothing will stop your destruction at their hands.'" If that wasn't acceptable to Dahar, said the vizier, then he should at least send away his family to some safe point in India. Dahar refused to do either. "I cannot send away my family to security while the families of my thakurs and nobles remain here."
Dahir then tried to prevent Qasim from crossing the Indus River, moving his forces to its eastern banks. Eventually, however, Qasim crossed and defeated forces at Jitor led by Jaisiah (Dahir's son). Qasim fought Dahir at Raor (near modern Nawabshah) in 712, killing him. After Dahar was killed in the Battle of Aror on the banks of the River Indus, his head was cut off from his body and sent to Hajjaj bin Yousuf.