Who is Thomas-Langlois Lefroy from Jane Austen's Letters and what is their importance?

Thomas-Langlois Lefroy was the "Irish friend" that Jane referred to as "Tom". He was educated in London at the expense of his great-uncle, who disapproved of the match between Tom and Jane. Jane loved Tom Lefroy very much. He later practiced law in Dublin, and he eventually married Mary Paul in 1799.