Where Angels Fear to Tread by FORSTER, E. M.

On a journey to Tuscany with her young friend and traveling companion Caroline Abbott, widowed Lilia Herriton falls in love with both Italy and a handsome Italian much younger than herself, and decides to stay. Furious, her dead husbands family send Lilias brother-in-law to Italy to prevent a misalliance, but he arrives too late. Lilia marries the Italian and in due course becomes pregnant again. When she dies giving birth to her child, the Herritons consider it both their right and their duty to travel to Monteriano to obtain custody of the infant so that he can be raised as an Englishman. (Summary from Wikipedia)