There are several theories with respect to the origin of the Blake surname. One school of thought states that Blake as a forename or surname originated from Old English. The word 'blac' referred to an individual with dark hair or skin and the word 'blaac' referred to an individual with pale hair or skin. Since both are pronounced 'Blake' the actual origin in this line of thought is unknown as it could pertain to either.
William Arthur in his 1857 publication of an etymological dictionary of names gives the following for the name Blake: 'A corruption of the British Ap Lake from Ap, signifying from, or son, and Lake, the son of Lake. The family went into Ireland with Strongbow (1169), where the name became corrupted into Blake.'
One of the fourteen Tribes of Galway in Ireland has the surname Blake. These Blakes were said to be descendants of Richard Caddell, alias Blake, who was with Strongbow in 1169. Richard used the surname Blake in Ireland and his descendants have continued to do so.
Edith Bartlett Sumner in her 1948 book on her Blake family states that the surname was locational having been taken from the land which they occupied known as 'Blakeland.' Of note, there is a parish located south east of Calne called Blackland (Black and Blacke were alternative spellings for the name Blake in the Andover Parish Register). Interestingly, there are thirty three individual entries (in various counties) with the name 'Blackland' when a search is done on the current map of Britain using the Ordnance Survey.
A recent find of a 'Blake' Pedigree created by the College of Arms (UK) has the spelling Blague alias Blaake. This chart is held by the Wiltshire and Swindon History Centre at Chippenham Wiltshire. The first entry on the chart is (top of the pedigree) (transcription) Richard Blague alias Blaake of Wiltshire Esquire temp Edward I et Edward 2. (end of transcription) Since Edward I was King of England from 1272 - 1307 and Edward II King from 1307 to 1327, this dates Richard between 1272 and 1327. A note on the chart mentions a gift by Richard to the Knights Templar of a piece of property in Essex during the reign of Edward I. The Knights Templar were disbanded in 1312 thus giving a smaller range for Richard as an adult between 1272 and 1307. The chart to which I am referring is four feet wide by twelve feet long. The origin of the spelling Blague is unknown. Dr. J.W. Donaldson (Fellow of Trinity College) in Cambridge Essays on page 62 includes Blague in his list of surnames (under Suffolk) for which no origin has been found at the time of writing (1856).
The name Robert de Blakeland appeared as early as 1286 in the Wiltshire Roll of Subsidies which had been granted to King Edward I. The Wiltshire chart has Richard Blague alias Blaake also living in this similar area and your group of authors is presently investigating whether indeed this is the same person in that the chart lists his wife as Ann Cole who was also recorded as marrying Robert de Blakeland by other family researchers.
The origin of the name Blake is also considered to be Old Norse first appearing in Yorkshire, England, possibly derived from the word Blaker referring to a village and a former municipality of Akershus county, Norway (east of Oslo).