Chapter 1 of _Mathilda_ in Lord Abinger's notebook is headed, "Florence Nov.9th.

1819." Since the whole of Mathilda's story takes place in England and Scotland, the date must be that of the manuscript.

Mary was in Florence at that time.
These dates are supported by entries in Mary's journal which indicate that she began writing _Mathilda_, early in August, while the Shelleys were living in the Villa Valosano, near Leghorn.

On August 4, 1819, after a gap of two months from the time of her little son's death, she resumed her diary.

Almost every day thereafter for a month she recorded, "Write," and by September 4, she was saying, "Copy." On September 12 she wrote, "Finish copying my Tale." The next entry to indicate literary activity is the one word, "write," on November 8.