Portrait of an Unknown Lady, 1650-55, by Joan Carlile was purchased on a hunch by dealer Bendor Grosvenor at a Woolley & Wallis sale in 2014 for £4200.
It was acquired by the Tate for £35,000.
Based in Covent Garden, Carlile (1606-79) was probably the first woman to work in Britain as a professional painter.
The portrait will be conserved before it is displayed in April. Portrait of an Unknown Lady, 1650-55 by Joan Carlile was purchased on a hunch by dealer Bendor Grosvenor at a Woolley & Wallis sale in 2014 for £4200.
It was acquired by the Tate for £35,000.
Based in Covent Garden, Carlile (1606-79) was probably the first woman to work in Britain as a professional painter.
The portrait will be conserved before it is displayed in April.