Hayley remembered her when comparatively young, a person of lively talents with a sweet serene countenance, and remarkably fond of reading.
There he resided apparently until 1748, when, upon his wife's request, he left the duty in the charge of a curate, and moved back to Huntingdon, where he occupied a ‘convenient house’ in the High Street, and prepared pupils for the university.
Ten weeks later Cowper removed, with Mary and her daughter Susanna, to Olney, in order to be under the more direct influence of John Newton.
His ‘spiritual and lively notions in religion’ had from their first meeting attracted Cowper, and from 1770 until his early death he became the poet's chief confidant and the recipient of many of the most delightful letters in the whole range of our literature.
Conspicuous among them is that masterpiece of its kind, dated 31 October 1779, in which Cowper accuses Johnson of plucking some of the most beautiful feathers from the wing of Milton's muse, and ‘trampling them under his great foot.’ [1] After her son's departure and her daughter's engagement to Matthew Powley, vicar of Dewsbury, Mary Unwin seems, at the close of 1772, to have become regularly engaged to Cowper (he being then forty-one and she forty-eight), but before the commencement of 1773, his mind had become once more grievously clouded, and the project of marriage was never to be realised.
Upon his recovery, she did all in her power to encourage him to write, and when he became an author he paid her the highest respect as an instinctive critic, and called her his lord chamberlain, whose approbation was his sufficient license for publication.
The extraordinary ‘fracas’, which disturbed the quiet round of domesticity at Olney in April 1784, was almost certainly due to Cowper's perception of a latent jealousy of Lady Austen in the mind of his older friend.
In 1793, her health was beginning to fail, and the poet inscribed to her the exquisite lines ‘To Mary,’ which Tennyson classed, with those ‘On the Receipt of My Mother's Picture,’ as too pathetic for reading aloud.