Oil on canvas, 173.99cm by 150.5cm. Signed: Angelica Kauffman/pinx 1771.
In Greek mythology Aethra was the mother of Theseus.
The Swiss artist, Angelica Kauffman, was one of two female founder members of the Royal Academy in 1768 and a particular favourite of Brownlow, 9th Earl of Exeter (1725-1793).
He had met her in Naples on his first Grand Tour in 1763 and the following year commissioned an exceptionally fine portrait from her, with Vesuvius in the background, PIC781.
He subsequently became one of her foremost patrons.