Short answers, pulled from the story.
Bhimber is a town and the headquarters of Bhimber District in Pakistan-administered Azad Kashmir. It lies about 47 kilometers southeast of Mirpur, in the corridor between Pakistan proper and the Jammu region of Indian-administered Kashmir.
Bhimber is called Baab-e-Kashmir, meaning Door to Kashmir, because of its position on the overland route from the Punjab plains into the Kashmir Valley. Mughal emperors used the town as their standard staging point on journeys to Srinagar, and its geographical position made it the natural entry point into the region.
The Chibhal dynasty held Bhimber as their capital from 1400 to 1856, a span of 456 years. The region came under Maharaja Gulab Singh in the 19th century, ending the dynasty's long tenure.
The Ain-i Akbari, compiled around 1595, listed Bhimber as a mahal within the Lahore Subah province and placed it in the Jech Doab. Bhimber's assessed revenue was recorded at 1,200,000 dams. The entry noted that Bhimber was not listed as supplying troops to the Mughal army.
Joan Blaeu, a Dutch cartographer, included Bhimber in the Atlas Maior, published in 1665. The town's name appears on page 19 of that work.
Jawahir Singh was accused of treacherous conspiracy by Maharaja Ranbir Singh in 1859 and forced into exile in Ambala. Ranbir Singh, who reigned from 1857 to 1885, paid Jawahir Singh an annual stipend of Rs. 100,000 until his death. Jawahir Singh left no heirs, so his territories, including Bhimber, were absorbed directly by Ranbir Singh.