In the spring of that year they went together, accompanied by Miss Clairmont, for a second time to Switzerland.

They reached Geneva on the 17th of May and were soon after joined by Lord Byron and his travelling physician, Dr.Polidori.Shelley had not yet made Byron's acquaintance, though he had sent him a copy of "Queen Mab", with a letter, which miscarried in the post.

They were now thrown into daily intercourse, occupying the villas Diodati and Mount Alegre, at no great distance from each other, passing their days upon the lake in a boat which they purchased, and spending the nights in conversation.

Miss Clairmont had known Byron in London, and their acquaintance now ripened into an intimacy, the fruit of which was the child Allegra.

This fact has to be mentioned by Shelley's biographer, because Allegra afterwards became an inmate of his home; and though he and Mary were ignorant of what was passing at Geneva, they did not withdraw their sympathy from the mother of Lord Byron's daughter.