The University of Toronto’s history of the G20, which Sam refers to in his post, was commissioned by the South African Chair in 2007 and was presented at the G20 meeting that year; the Lowy Institute is actually cited a couple of times in that paper.
It is as good a source as we have at the moment in establishing how the G20 came into being. It shows very clearly the fairly accidental nature of its establishment. Following the Asian Financial Crisis (and the earlier Latin American financial crises) it became clear that the G7 group of finance ministers and central bank governors needed to consult with increasingly important emerging countries.
The AFC demonstrated that the developing world was, by the end of the 1990s, firmly entrenched in the international financial system; crises in the developing world now had major impacts in New York, Frankfurt, London and Tokyo.
But the G20 wasn’t the first port of call. A G22 was called together in 1998 and met twice. The University of Toronto’s G20 history credits Singaporean Prime Minister Goh for suggesting to President Clinton that he call together a wider group of countries. In 1999, a G33 was called together and also met twice.
So, perhaps credit for the creation of the G20 should in fact go to Singapore, a non-member country. Singapore has received invitations to the last two summits (Seoul and Cannes) in its capacity as Chair of the 3G (Global Governance Group) countries.