The Rai Dynasty (c. 416–644 CE) was a dynasty based in Sindh, which ruled much of the Northwestern regions of the Indian Subcontinent. The influence of the Rais extended from Kashmir in the east, Makran and Debal port (modern Karachi) in the west, Surat port in the south, and the Kandahar, Sulaiman, Ferdan and Kikanan hills in the north. It ruled an area of over 600,000 square miles (1,553,993 km2), and the dynasty reigned a period of 143 years.
The Battle of Rasil in 644 played a crucial role in their decline. The battle resulted in the Makran coast being annexed by Rashidun Caliphate. The book Chach Nama chronicles the final demise of the Rai dynasty and the ascent of the Hindu Chach of Alor to the throne.
The emperors of this dynasty were great patrons of Hinduism and Buddhism. They established a formidable temple of Shiva in present-day Sukkur, Pakistan, close to their capital in Al-ror. This is consistent with the historical accounts from the times of Ashoka and Harsha, as numerous monarchs from the Indian Subcontinent never sponsored a state religion and usually patronised more than one faith.
Rai dynasty Wikipedia
B. D. Mirchandani says, "Our knowledge of the Rai dynasty, which is not a great deal, is derived entirely from three Muslim chronicles of Sind." The history of the Rai and Brahman dynasties is almost entirely dependent on the Muslim chronicles, especially the Chachnama and Shahnama.
Their rise to power in the time of shifting political scenes with the wane of the Sassanid influence in the wake of the Hepthalite (White Hun/Huna) invasions, and with the rulers issuing silver coins bearing their likeness by the 7th century.
The Chachnama describes that Rai dynasty was an important Brahmin dynasties of that time and the extant of Rai Sahiras' domain:
The limits of his dominions extended on the east to the boundary of Kashmir, on the west to Makran, on the south to the coast of the sea and Debal, and on the north to the mountains of Kurdan and Kíkánán. He had appointed four Governors (Maliks) in his kingdom: one at Brahminabad; and the fort of Nerun and Debal, Luhánah, Lákhah. Sammah and the river were left under his management. Another at the town of Siwis-tán; and Ladhia, Chingán, the skirts of the hills of Rojhán up to the boundary of Makrán, were given into his charge. The third at the fort of Iskandah; and Báhíah, Stwárah, Jajhór, and the supplementary territories of Dhanód were given in his possession; and the fourth at the town of Multan; and the towns of Sikkah, Karnd, Ishthar and Kíh up to the boundary of Kashmir were en¬trusted to him. The king himself had his headquarters in the city of Aror, retaining Kurdán, Kíkánán, and Bar-hamas directly under his sway.
According to the Chachnama, the last Rai emperor, Rai Sahasi II, died through illness without any issue. By that time Chach was in complete control of the affairs of the kingdom. However, when Rai Sahasi II was near to death, Suhanadi explained to Chach that the kingdom would pass to other relatives of the dying king in absence of any direct heir to the kingdom. Consequently, they kept secret the news of the king's death until claimants to the throne were killed through conspiracy. Following this, Chach declared himself ruler and later married Suhandi. This ended the Rai Dynasty and began the dynasty of another Brahmin dynasties called Chach dynasty.
Six months after death of Rai Sahasi his brother, Rana Maharath of Chittor, challenged Chach in combat, claiming to be rightful ruler of the Rai Dynasty. Chachnama states that Maharath was killed as the two engaged in a duel, in which it was forbidden to mount a horse or any other animal. During the duel Chach mounted a horse in order to kill his rival.
Andre Wink reports on the possibility of the corruption of the Sanskrit names and renders them as related in parenthesis in the following chronology of the Rai rulers of Sindh:Rai Diwa ji (Devaditya), a powerful chief who forged alliances and extended his rule east of Makran and west of Kashmir, south to the port of Karachi and north to Kandahar
Rai Sahiras (Shri Harsha)
Rai Sahasi (Sinhasena)
Rai Sahiras II, died battling the King of Nimroz
Rai Sahasi II, the last of the line