Bir was ruled by the Pal dynasty of the Chandarvanshi lineage. The last Raja or Rai was Raizada Prithi Pal, who was a descendant of the Rajas of Bhangahal, who appear to have maintained their rights until the time of Raja Prithi Pal in the early part of the eighteenth century. Raja Prithi Pal fell victim to his father-in-law, Raja Sidh Sen, who in 1728 invited him to Mandi on the pretext of seeking his assistance against the Raja of Suket. He was kindly received, but within a month of his arrival he was beguiled into the Damdama Fort, and there murdered. It is said his body was duly burnt, but his head was buried in a tank facing the Mandi Raja's palace.
A pillar was erected on the spot, and a light was kept burning on it for years. Sidh Sen's object in murdering Raja Prithi Pal was to seize his territory, but in this he only partially succeeded. The forts at Jagapur, Tika Thana and the Patgana of Nir, with eighteen villages of Ilaga Chuhar (all of them until then forming part of the Bhangahal kingdom) were annexed to Mandi. Subsequently, Sidh Sen sttempted to seize Karanpur, which also belonged to Bhangahal, but he was repulsed by Raja Raghunath Pal who had succeeded his father Raja Prithi Pal. In a second invasion, he penetrated as far as Kotharli Gulu, then in Bhangahal, but Raghunath Pal was able, with the assistance of Raja Thedi Singh of Kulu, not only to check his advance, but also to beat him back with considerable loss.