The recognition that geo-technologies are playing an increasingly important role in historical research led to a meeting in Barcelona in December 2007, attended by fifty leading academics and GIS practitioners from Europe, with additional representation from leading North American experts. The conference benefited from previous meetings in Florence (2000), Ghent (2002), Amsterdam (2004), Belfast (2005), Berlin (2006), and Mainz (2007). The three-day Barcelona conference had three key aims: (1) to survey the use and maturity of historical GIS; (2) to hold an inclusive, facilitated discussion on the feasibility and requirements for a European historical GIS; and (3) to develop a white paper on how to advance historical GIS within Europe. A network of networks was a major proposal to come from the Barcelona meeting, and its outlines and rationale are advanced in this white paper.