New party was officially registered on 15 October 2006 under the name Pro Patria and Res Publica Union.

Together with its predecessors the Pro Patria Union was the main force behind the economic and legal reforms in the Republic of Estonia at the beginning of the 1990s.

The party had one seat in the European Parliament, held by Tunne Kelam, the chairman of the Pro Patria Union from 7 December 2002 to 16 April 2005.

For the local elections in autumn 2005, the Pro Patria Union signed a cooperation agreement with two minor parties: Union of Farmers (Põllumeeste Kogu) on 6 July 2005 and with Estonian Democratic Party (Eesti Demokraatlik Partei) on 12 July 2005.

In April 2006, former party leader and twice PM Mart Laar was awarded the Friedman Prize for Liberty.