She wrote and published extensively on both secular and religious topics ranging from translation, poetry, letters, children's literature and biography.
In 1784 she travelled to London with her father and paid several visits to Burke's town house, where she met Sir Joshua Reynolds and George Crabbe.
She also went to Beaconsfield, and on her return wrote a poem in praise of the place and its owner, which was acknowledged by Burke, 13 December 1784, in a long letter.
On 6 January 1791 she married William Leadbeater, a former pupil of her father and a descendent of the Huguenot Le Batre and Gilliard families.
[3] William was orphaned as a young age and was placed in the boarding school ran by Mary's father Richard Shackleton.
She was in Carlow on Christmas Day 1796 attending a Quaker meeting when the news arrived that the French fleet had been seen off Bantry.
They seized the tools of local blacksmith Owen Finn so as to prevent him from making pikes and other weapons for the United Irishmen.
The soldiers tortured and flogged the inhabitants of Ballitore in an attempt to extort confessions about the location of pikes and weapons.
The bodies of those killed lay in the streets of Balliotre and nearby fields and ditches for days as their families were unable to bury them due to the danger of being shot or injured themselves.
Leadbeater reported that there was no cured bacon sold in Ireland for several months after the rebellion as there was "the well-founded dread of the hogs having fed upon the flesh of men.
[18] In 1808 she published Poems with a metrical version of her husband's prose translation of Maffæus Vegio's Thirteenth Book of the Æneid.
The lives are those of real persons, and contain some interesting passages, especially in the life of James Dunn, a pilgrim to Loch Derg.
Many traits of Irish country life appear in these books, and they preserve several of the idioms of the English-speaking inhabitants of the Pale.
Her Biographical Notices of Members of the Society of Friends who were resident in Ireland appeared in 1823, and is a summary of their spiritual lives, with a scanty narrative of events.