has changed several times since the middle of the 19th century. 1844–1911 Worcestershire contained numerous exclaves, which were areas of land cut off from the main geographical area of Worcestershire and completely surrounded by the nearby counties of Warwickshire, Staffordshire, Gloucestershire, Herefordshire and Oxfordshire. The most notable islands were Dudley, Evenlode, Blockley and the area around Shipston-on-Stour. Herefordshire, Staffordshire, Warwickshire and Shropshire had their own exclaves within the main part of Worcestershire at Rochford, Broome, Clent, Tardebigge (Tutnall and Cobley) and Halesowen respectively. Tardebigge's history outside the county is even more colourful, changing hands from Worcestershire to Staffordshire and Warwickshire, before returning to Worcestershire at differing times over the centuries. The southern boundary of the county was also complex, with parish boundaries penetrating deep into Gloucestershire and vice versa. Worcestershire County Council came into existence following the Local Government Act 1888 and covered the historic traditional county, except for two designated county boroughs at Dudley and Worcester. Birmingham's continuous expansion has been a major cause of Worcestershire's fluid boundary changes and associated housing issues. The district of Balsall Heath, which had originally constituted the most northerly part of the parish of King's Norton, was the first area of the county to be added to the County Borough of Birmingham, on 1 October 1891. This was followed by Quinton Urban District, which was ceded to Birmingham in November 1909, and then by the Rural District of Yardley and the greater part of the Urban District of King's Norton and Northfield, which were absorbed into Birmingham under the Greater Birmingham Scheme on 9 November 1911. Thus these areas were transferred from Worcestershire to Warwickshire. Dudley's historical status within the Diocese of Worcester and through its aristocratic links ensured that the exclave was governed on a largely autonomous basis. Worcester was designated a county corporate, and thus became separate from the rest of Worcestershire. 1926 boundary changes In 1926, Dudley County Borough council purchased several square miles of land to the north of the town centre, mostly in Sedgley (Staffordshire), including Dudley Castle. This was to build the Priory Estate, a large new council estate on which construction began in 1929. The boundaries of Worcestershire were altered to include all of the proposed new housing estate in Dudley. 1966–1974 During the Local Government reorganisation of April 1966, Dudley expanded beyond its historical boundaries and took in the bulk of Sedgley, Brierley Hill and