What is the main purpose of Marquesa's letters?

María seeks comfort in her writing—which eventually leaves its mark on Spanish literature—and in the bottle, which causes her disgrace in Lima. When Clara has a daughter María goes to a mountain religious retreat to meditate. There she reflects on her ways, decides she will do better in the future, but dies with the collapse of the bridge of San Luis Rey. The account of her letter writing is based on the true history of Mme. de Sévigné.