"What, are you that damned atheist Shelley?" and felled him to
the ground. Often he would go half frantic with delusions--as
that his father and uncle were plotting to shut him up in a
madhouse, and that his boy William would be snatched from him
by the law. Ghosts were more familiar to him than flesh and
blood. Convinced that he was wasting with a fatal disease, he
would often make his certainty of early death the pretext for
abandoning some ill-considered scheme; but there is probably
much exaggeration in the spasms and the consumptive symptoms
which figure so excitedly in his letters. Hogg relates how he
once plagued himself and his friends by believing that he had
elephantiasis, and says that he was really very healthy The
truth seems to be that his constitution was naturally strong,
though weakened from time to time by neurotic conditions, in
which mental pain brought on much physical pain, and by
irregular infrequent, and scanty meals.

In February 1817 he settled at Marlow with Mary and Claire.
Claire, as a result of her intrigue with Byron--of which the
fruit was a daughter, Allegra, born in January--was now a
permanent charge on his affectionate generosity. It seemed
that their wanderings were at last over. At Marlow he busied
himself with politics and philanthropy, and wrote 'The Revolt
of Islam'. But, partly because the climate was unsuitable,
partly from overwork in visiting and helping the poor, his
health was thought to be seriously endangered. In March 1818,
together with the five souls dependent on him-- Claire and her
baby, Mary and her two babies (a second, Clara, had been born
about six months before)--he left England, never to return.