Groningen Growth and Development Centre (Historical Development)Offers three datasets:
Maddison Historical Statistics - estimates of GDP per capita for countries from AD 1 to 2010 (based on the print publication - World economy: historical statistics 2003, A. Maddison HC 15 - library, floor 3)
Historical National Accounts - detailed estimates of GDP (down to industrial/sector level) for countries, 19th & 20th centuries
Modern Times - data on technology & economic performance for European countries in 1910, 1935 & 1950