Blackburn Hundred (also known as Blackburnshire) is a historic sub-division of the county of Lancashire, in northern England. Its chief town was Blackburn, in the southwest of the hundred. It covered an area similar to modern East Lancashire, including the current districts of Ribble Valley (excluding the part north of the River Ribble and east of the Hodder, which was then in Yorkshire), Pendle (excluding West Craven, also in Yorkshire), Burnley, Rossendale, Hyndburn, Blackburn with Darwen, and South Ribble (east from Walton-le-dale and Lostock Hall). Much of the area is hilly, bordering on the Pennines, with Pendle Hill in the midst of it, and was historically sparsely populated. It included several important royal forests. In the 18th century several towns in the area became industrialized and densely populated, including Blackburn itself, and Burnley. Early history The shire probably originated as a county of the Kingdom of Northumbria, but was much fought over. In the Domesday Book it was among the hundreds between the Ribble and Mersey rivers ("Inter Ripam et Mersam" in the Domesday Book) that were included with the information about Cheshire, though they are now in Lancashire and cannot be said clearly to have then been part of Cheshire. The area may have been annexed to the embryonic Kingdom of England following the Battle of Brunanburh in 937. The Domesday Book entry shows that before the Norman conquest, the hundred had been held directly by King Edward. It mentions royal holdings in Blackburn, Huncoat, Walton-le-Dale and Pendleton, and those of a church at Blackburn and St Mary's in Whalley. Also it talks of 28 freemen holding land as manors, but gives no further details about them. After the conquest Blackburnshire was part of a large area given to Roger de Poitou and he had demised it to Roger de Busli and Albert de Gresle. Domesday also mentions a sizable area of woodland. Two areas, the first one league long and as wide, and another six long and four leagues wide, which could be as much as . Later the much the east of the hundred was established as royal hunting grounds, Known as the forest of Blackburnshire it was divided into the four forests of Accrington, Pendle, Trawden and Rossendale. Feudal period At the start of the 12th century Roger de Poitou joined the failed rebellion against King Henry I in favor of his brother Robert Curthose, as