Angus Maddison (1926-2010) was a British economist who specialised in systematically collating detailed quantitative data on long term global economic history. His magnum opus is Contours of the World Economy, a sweeping 450 page summary of the growth and dynamics of the world economy from 1 AD to 2030, published in 2007 by Oxford University Press. In 2001 he had estimated that the world's output in the year 1 AD was $105.4 billion in 1990 prices.
A shorter, but similar and equally rigorous essay, by Maddison called Growth and Interaction in the World Economy: The Roots of Modernity is available HERE. The image above shows his Table 1.