By the time the Shelley party came back from Chamonix, the problem of Claire, now well into her fourth month of pregnancy, was becoming acute. On the evening of their return, all three of them dropped in on Byron at Diodati and talked with him until twelve, their fatigue after the journey making for a relatively early night. Mary records in her diary that on three of the five subsequent evenings they also visited Byron, but on the sixth (2nd August) she writes: ‘S. & C. go up to Diodati. I do not for Lord B. did not seem to wish it.’ This has been interpreted as an indication of a council of war about Claire's future, from which it was thought best that Mary should be excluded. One possible reason for this interpretation is that Mary's entry is followed immediately by one in which she notes that Shelley had come back that evening from Diodati with a letter from his lawyer which suggested he ought to return to England. There seems little doubt that Shelley's financial difficulties did require his presence back home, but the arrangements made with, and for, Claire meant that he needed to be there quite soon in any case.

In the aristocratic circles in which Byron had often moved, attitudes to illegitimate children tended to be relaxed. When he himself had been married, in the home of the otherwise pious and strait-laced Milbankes, the officiating clergyman had been a bastard son of Annabella's rich uncle, Lord Wentworth. At the other end of the social scale, the disruption of children born out of wedlock could be smoothed over with money.