The Alstons are said to have been established in the lands of Thinacre Milne (= Mill), in Lanark-shire, from the fourteenth century.
According to a seventeenth-century tradition the ancestor of the Scottish Alstons fled to Scotland from England during the reign of Edward II (1302-1327), as a retainer of Hamilton, who had killed Lord Spencer in a duel. Hamilton was pursued and to escape he disguised himself as a sawyer. Alston rode on with Hamilton's clothes and horses, acting as a decoy. This incident, according to the story, is the origin of the Hamilton crest: an oak tree being cut by a frame-saw.
Hamilton supported Bruce in the Wars of Independence and was later granted the lands of Cadzow. He, in turn (in the tradition), granted Thinacre Milne to the Alstons.
Hugo de Alston is named in a charter of 1399. Another Hugo de Alston, possibly his son, died in 1425. This second Hugo is described as Dominus de Candor (Lord of Candor). Hugo's heir was his only daughter, Margaret, who married one of the Hamiltons of Cadzow. Thus the line of the Alstons of Candor died out.
At some later date Alstons became established at Thinacre Milne, Lanark-shire. The earliest recorded Alston of Thinacre Milne is John Alston, who was born in the mid-sixteenth century. There were six generations of Alstons here, the last being Thomas, who died unmarried in the late eighteenth century. There had been an attempt to dispossess the family in 1772. This was abandoned but the property was sold off piece by piece. The family burial place at Hamilton was destroyed when church was leveled to extent the Duke of Hamilton's parks.
Information on the early history of the Alstons was collected by Charles Alston (1685-1760), Professor of Botany and Medicine in the University of Edinburgh. He, in turn, relied on information recorded by the antiquary, George Crawfurd (d. 1785) and on information from individuals who knew something of the family history. Charles Alston's manuscript is in Edinburgh University Library (Ms Cat. La III 375).