|Full name||Dahir Sen|
|Successor||Muhammad Bin Qasim|
|Father||Chach of Alor|
|Mother||Rani Suhanadi (Former wife of Rai Sahasi)|
Raja Dahir (Sindhi: راجا ڏاھر Sanskrit: राजा दाहिर Urdu: راجہ داہر, 661–712 AD) was the last Hindu ruler in Sindh and parts of the Punjab in modern Pakistan. At the beginning of the Muslim conquest in the Indian subcontinent, his kingdom was conquered by Muhammad bin Qasim (an Arab general) for the Umayyad Caliphate.
Reign in the Chach Nama
The Chach Nama is the oldest chronicles of the Arab conquest of Sindh. It was translated in Persian by 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 Muhammad bin Qasim). It was considered to be a romance until Mountstuart Elphinstone's observations of its historical accuracy.
The Chach Nama describes Raja Dahir as a Pushkarna Brahmin king, son of Chach of Aror, who ascended the throne at the death of his uncle Chandar. Dahir's sister, Dahar, grew up in Aror with their elder brother Dahar-Sena (who arranged her marriage to King Sohan of Bhatia). She then moved to the capital, Aror, with Dahir before her marriage. However, to avoid a prophecy that his husband would rule a strong kingdom from his capital at Aror, Dahir is reported to have married her; the marriage resulted in severe criticism and a conflict with their brother, Dahar-Sena. Dahar-Sena assembled an army and marched on Dahir, because died of sunstroke while besieging Dahir at Aror. Dahir then subdued the area, consolidating his base of support base by executing his nephew Chach (Dahar-Sena's son). He married his brother widow, who was the sister of Sarhand Lohanah (a chieftain who commanded the allegiance of several Jat tribes).
Eight years later, Dahir's kingdom was invaded by Ramal at Kannauj. After initial lose, the enemy advanced on Aror and he allied himself with Alafi, an Arab. Alafi and his warriors (who were exiled from the Umayyad caliph) were recruited; they led Dahir's armies in repelling the invading forces, remaining as valued members of Dahir's court. In are later war with the caliphate, however, Alafi served as a military advisor but refused to take an active part in the campaign; as a result, he later obtained a pardon from the caliph.
War with the Umayyads
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. The chronicles reports that when he heard about the matter, Hajjaj write a letter to Dahir and launched a military expedition when no resolution could be reached. Other reasons for the Umayyad interest in a foothold in the Makran, Balochistan and Sindh regions were the participation of Sindhi's armies with the Persians in battles (such as those at Nahawand, Salasal and Qādisiyyah) and granting refuge to fleeing rebel chieftains.
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.
The Chach Nama describes rule by successors of the Rai Dynasty as characterized by persecution of Buddhists, Jats and Meds from the time of Chach; a prophecy of Raja Dahir's fall encouraged defections to bin Qasim's army. Sociologist U.T. Thakur suggested a more complex dynamic: Hinduism (the religion of the dominant castes), Buddhism (the religion of the lower castes) and high Buddhists were descended from Bactrian migrants. The king was a Brahmin, and the majority of his advisers were from his family. The ruler of Alor (a Jat) professed Buddhism. Nonetheless, there was a sense of "ideological dualism" between them; Thakur considered this the inherent weakness exploited by the Arabs when they invaded the region.
By enlisting the support of local tribes (such as the Jats, Meds and Bhuttos) and Buddhist 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.
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; Dahir's wife immolated herself (with other women in her household) in accordance with the Hindu tradition of Jauhar.
After the death of Caliph Walid I, Muhammed bin Qasim end was more tragic than that of general Musa bin Nusayr. Muhammed bin Qasim was a nephew of Hajjaj bin Yusuf, governor of Iraq. The new caliph, Sulaiman, disliked Hajjaj; however, the latter died before Sulaiman could punish him. The caliph then turned against Hajjaj’s relatives, and Muhammed bin Qasim was dismissed and sent back to Iraq. The new governor of Iraq, Saleh bin Abdur Rahman, hated Hajjaj because the latter had killed Saleh’s brother. Saleh also turned against Hajjaj’s relatives; Muhammed bin Qasim was arrested and imprisoned because of his relationship to Hajjaj. In prison, he was blinded, tortured and murdered.
- Wink, 153
- Common Era year is an approximation of the Islamic calendar date 613 AH.
- Mirza Kalichbeg Fredunbeg: The Chachnamah, An Ancient History of Sind, Giving the Hindu period down to the Arab Conquest. Commissioners Press 1900, Section 14  Then Dáhar wrote a letter to his brother, couched in gentle words, and in it he referred to the horoscope of Bái, and said: “The astrologers divined, by means of their science, that this princess would be the queen of Alór, and her husband would be the king who was to hold fast all these territories. To remedy and avert this unpleasant consequence, I took it upon myself to commit this shameful breach of royal etiquette and social rules. We now make the apology that what we considered expedient to do was done through necessity, and not of our own free will. Do therefore excuse us.”
- Mirza Kalichbeg Fredunbeg: The Chachnamah, An Ancient History of Sind, Giving the Hindu period down to the Arab Conquest. Commissioners Press 1900, Section 18: "It is related that the king of Sarandeb* sent some curiosities and presents from the island of pearls, in a small fleet of boats by sea, for Hajjáj. He also sent some beautiful pearls and valuable jewels, as well as some Abyssinian male and female slaves, some pretty presents, and unparalleled rarities to the capital of the Khalífah. A number of Mussalman women also went with them with the object of visiting the Kaabah, and seeing the capital city of the Khalífahs. When they arrived in the province of Kázrún, the boat was overtaken by a storm, and drifting from the right way, floated to the coast of Debal. Here a band of robbers, of the tribe of Nagámrah, who were residents of Debal, seized all the eight boats, took possession of the rich silken cloths they contained, captured the men and women, and carried away all the valuable property and jewels." 
- Sindhi Culture by U.T Thakur, Bombay 1959.
- Ahmed, Nazeer. "The Conquest of Sindh". Blog at WordPress.com. Retrieved March 9, 2013.
- Mirza Kalichbeg Fredunbeg: The Chachnamah, An Ancient History of Sind, Giving the Hindu period down to the Arab Conquest. Translated by from the Persian by, Commissioners Press 1900 
- Thakur Deshraj: Jat Itihas, Delhi, 1934
- R.C. Majumdar, H.C. Roychandra and Kalikinkar Ditta : An Advanced History of India, Part II,
- Tareekh-Sind, By Mavlana Syed Abu Zafar Nadvi
- Wink, Andre, Al Hind the Making of the Indo Islamic World, Brill Academic Publishers, Jan 1, 1996, ISBN 90-04-09249-8
Abdullah Khan Dahir