Conversation so far:
When was the Paris Peace Conference?
1919
What happened at the Paris Peace Conference for Billy Hughes?
Hughes remained away for 16 months, and signed the Treaty of Versailles on behalf of Australia – the first time Australia had signed an international treaty.
What did the Treaty of Versailles entail?
The Treaty of Versailles was the most important of the peace treaties that brought World War I to an end.

Question: Who was at the conference?
Self-contained rewrite: Who was at the Paris Peace Conference?