In 1670 the Beales, who were originally from Suffolk, were offered the chance to lease a newly-built house on Pall Mall by a distant relation. They seized the opportunity as they, rightly, predicted that wealthy new clients would also be moving to the area, which was situated opposite the fashionable St James’s Square. Indeed by the mid-1670s Mary, who was largely self-taught, was earning over £400 a year painting portraits, enjoying the peak of her commercial success.

Charles Beale, Mary’s husband and studio manager, categorised Mary’s painting output into three groups: those ‘for study and improvement’, ‘for friends and in return for kindness’, and ‘for profit’. The Beales sometimes used unorthodox materials - for example, painting upon bed ticking for more experimental oil studies - and were clearly mindful about production costs. That the present portrait, which has an air of formality about it, was painted on canvas and has been adorned with a simulated carved stonework cartouche suggests that this was painted ‘for profit’. These decorative trompe l’oeil cartouches are found in many of Beale’s portraits from the 1670s and '80s that were commissioned by paying clients. It was a visual device that was also popular with Beale’s contemporaries, like her supporter Sir Peter Lely. Whilst Lely would have employed studio assistants to paint the cartouches for him, Beale actually paid her own children to paint these same decorative motifs for her portraits.

As patronage from the gentry and nobility dwindled after the death of Lely in 1680, her later works - such as the present example - were mostly portraits of those in her close circle of friends and family. Her last years were spent in their house on Pall Mall and after her death in the autumn of 1699, she was buried in St James’s Church in Piccadilly.

The sitter of our portrait is thought to be Lady Mary Sadleir (d. 1706), who was painted by Mary Beale alongside a pendant of her second husband, Sir Edwin Sadleir, around the same time as our portrait (this pair is now kept at Sutton House in London). Lady Sadleir is best remembered today for her bequest to Cambridge University, which funded the Sadleirian Professor of Pure Mathematics.