Barnet, also known as Chipping Barnet, was historically a chapelry of the parish of East Barnet, and became a separate parish by 1500. Although East Barnet was the parent parish, Barnet was the main town (Chipping means "market") and grew up at a major junction one of the main roads out of London to the north.
From an early time the town straddled three parishes - Barnet parish covered the southern parts of the town whilst the north-east fell into Monken Hadley parish and the north-west was in South Mimms parish, both of which were in Middlesex, whereas Barnet was in Hertfordshire.
In 1894 the town was unified when Monken Hadley and South Mimms parishes were both split, creating new parishes called Hadley and South Mimms Urban respectively, which both joined Barnet to become the Barnet Urban District. At the same time, two sections of Barnet parish were made separate parishes: Arkley, covering a rural area to the west of the town, and Barnet Vale, covering the growing suburban area to the east of the town. Arkley's independence was shortlived - it was absorbed into Barnet Urban District in 1905. Barnet Vale was never administered separately - from its creation in 1894 it was part of East Barnet Urban District. Both Barnet and East Barnet Urban Districts were abolished (with all their constituent parishes) in 1965, becoming parts of the London Borough of Barnet along with Finchley, Friern Barnet and Hendon.
In Saxon times the site was part of an extensive wood called Southaw, belonging to the Abbey of St Albans. The name of the town appears in early deeds as 'Bergnet' - the Saxon word 'Bergnet' meant a little hill (monticulus). Barnet's elevated position is also indicated in one of its alternative names ('High Barnet'), which appears in many old books and maps, and which the railway company restored. The area was historically a common resting point on the traditional Great North Road between the City of London and York and Edinburgh.
This was the site of the Battle of Barnet in 1471 (more accurately, Hadley), where Yorkist troops led by King Edward IV killed the rebellious "Kingmaker" Richard Neville, Earl of Warwick and Warwick's brother, John Neville, 1st Marquess of Montagu. This was one of the most important battles of the Wars of the Roses. Barnet Hill is said to be the hill mentioned in the nursery rhyme "The Grand Old Duke of York".
It is also the site of an ancient and well-known horse fair, whence comes the rhyming slang of Barnet Fair or barnet for 'hair'. The fair dates back to 1588 when Queen Elizabeth I granted a charter to the Lord of the Manor of Barnet to hold a twice yearly fair.