Mapley, Mabley, Mablye, Mapperley - all related names, which changed over time as births/bapstims/marriages were recorded/misspelt.

Often a child was only registered at the date of baptism, not always at birth, since only the church had a register with a degree of literacy not always available to family members. Parents even baptised children 2 or 3 at a time, to save money, leading to difficulties in ascertaining actual ages and birthdates.
In reality church records of baptism, marriage, death are the more reliable records going back in time...

So where does the name come from? There are a number of possible sources :- "Amabile" (likeable) ==> Mabilie ==> Mabel ==> Mabley / Mapley / Maples.
Or is the name associated with the Maple tree? Coincidentally, the Anglos-Saxon for maple tree is "hlin", which is used as part of the names of Great and Little Linford, from which many Mapleys hail after the 1770's.

The use of surnames was not a common practice in Europe, except among the noble classes, until the mid-sixteenth century.

Mabilie (ie. "Mabley") was the original Norman name that came over to England with the Norman conquests in 1066. It was first recorded in the 12th century as a baptismal name when Rogerus fillius ("son of") Mabilie appeared in the pipe rolls of Northamptonshire for the year 1130, in the reign of Henry I.

The Mapley surname is generally thought to be an Anglo-Saxon locative name (meaning one who lives near Maple trees) that originated in England. One early example is Robert atte Mapele, who lived in Essex in 1285 AD.

The surname Mapley was first found in Essex, where the first record found was that of Robert atte Mapele who was listed here in the Assize Rolls of 1285. Later John Mapel was recorded in the Subsidy Rolls for Cambridgeshire in 1327 and John del Mapples, was found in Sheffield in 1348.

Another source claims the name is from "Mepal; a location name in Cambridgeshire." This parish, in the hundred of South Witchford and Isle of Ely, has a very different etymology. It dates back to the 12th century when it was known as Mepahala and literally meant "nook of land of a man called Meapa," from the Old English personal name + "ham." The aforementioned Cambridgeshire rolls entry in 1327 with the spelling of "Mapel" may be related.

The earliest record of any variation of this surname is that of Robert de Maples which appears in the Devonshire tax rolls from 1273. These rolls, were a series of census and tax records kept by the English Treasury by order of King Henry II, with the oldest dating back seven hundred years to the 12th century.

Over time the name has been anglicised with it first becoming Mabley then Mapley and other variants. In the semi-literate society of the 1600s and 1700s the spelling of the name was prone to change if a family moved from one area to another. Examples of this are the mutation of Buckinghamshire Mableys to Mapley, Mapley to the London Mappley and the widespread conversion from Mably to Mabley whenever Mablys left their traditional Cornish base. Mable and Mabell seem to have been similarly interchangeable

. There appear to be several independent families characterised by geographic location and different spelling of the name, with no discernable common source. Some variation of the spelling of the name has occurred within succeeding generations e.g. some Mapleys have evolved from Buckinghamshire Mableys, some Cornish Mablys became Mableys when they moved away from Cornwall and the Kentish Maverleys mutated into Moverleys.

In 1841, 40% of all UK Mapleys (133 in total) were registered in Buckinghamshire, 21% in London, and the rest scattered throughout the UK. Only 10% of UK Mableys (193 in total) were based in Buckinghamshire, 40% of Mableys in Cornwall and 19% in London.

Around 1900 there were in England roughly equal numbers of Maberlys, Maberleys and Mabberleys (approx 70 of each) and roughly equal populations of Mablys and Mableys (100+ of each). There was also a healthy population of Mabels and Mables (approx 100 of each). There were however over 200 Mapleys. Only 25 Mapperleys were counted.