Augusta Maria Leigh was the only surviving daughter of John "Mad Jack" Byron, the poet Lord Byron's father, by his first wife, Amelia, née Darcy.

Captain John Byron was a British Army officer and letter writer, best known as the father of the poet Lord Byron. In 1824, an obituary of his son gave him the nickname "Mad Jack Byron", and though there is no evidence for this in his own lifetime, it has since stuck – certainly he was called "Jack" by his family members and referred to himself as such.