On 26 March 1995, Portugal started to implement Schengen Area rules, eliminating border controls with other Schengen members while simultaneously strengthening border controls with non-member states. In 1996 the country was a co-founder of the Community of Portuguese Language Countries (CPLP) headquartered in Lisbon. In 1996, Jorge Sampaio became president. He won re-election in January 2001. Expo '98 took place in Portugal and in 1999 it was one of the founding countries of the euro and the eurozone. On 5 July 2004, José Manuel Barroso, then Prime Minister of Portugal, was nominated President of the European Commission, the most powerful office in the European Union. On 1 December 2009, the Treaty of Lisbon entered into force, after it had been signed by the European Union member states on 13 December 2007 in the Jerónimos Monastery, in Lisbon, enhancing the efficiency and democratic legitimacy of the Union and improving the coherence of its action. Ireland was the only EU state to hold a democratic referendum on the Lisbon Treaty. It was initially rejected by voters in 2008.