Conversation so far:
What were George Bernard Shaw's first political activities?
On 5 September 1882 George Bernard Shaw attended a meeting at the Memorial Hall, Farringdon, addressed by the political economist Henry George.
Was George Bernard Shaw an active member?
George Bernard Shaw was not impressed by the SDF's founder, H. M. Hyndman, whom he found autocratic
Is there any additional information about George Bernard Shaw's time with the SDF?
George Bernard Shaw doubted the ability of the SDF to harness the working classes into an effective radical movement and did not join it.
What did George Bernard Shaw get involved with next?
George Bernard Shaw became a member of the recently formed Fabian Society in September.
How did George Bernard Shaw involve himself in it?
George Bernard Shaw went to the society's next advertised meeting, on 16 May 1884.
What did George Bernard Shaw do as a member of the committee?
George Bernard Shaw had provided the society with its first manifesto, published as Fabian Tract No. 2.
Is there information about the manifesto?
no

Question: When did he come to believe in Marxism?
Self-contained rewrite: When did George Bernard Shaw come to believe in Marxism?