On 26 April 1917 according to the calendar then used in Russia (9 May in the new style), the First Congress of Latgale Latvians opened in Rēzekne, in the Diāna cinema. Under the leadership of Francis Trasuns, the delegates adopted a historic decision: the Latvians of Latgale were one people with the Latvians of Vidzeme and Kurzeme, and Latgale should unite with the other Latvian regions. This vote became one of the key preconditions for the creation of the Latvian state in 1918.

After the February Revolution of 1917, Latvian political thinking still focused mainly on autonomy rather than full independence. The Latgale Congress was decisive because it politically joined historically separated Latgale with the other Latvian lands; without that decision, Latvia’s borders and identity would have developed differently.