On 21 April 1990, at Daugava Stadium in Riga, the Latvian Popular Front organized the All-Latvia Assembly of People’s Deputies—a dramatic pre-vote before 4 May. It brought together 8,086 deputies of all levels from parishes, towns, cities, and districts, and 8,003 of them supported the Appeal to restore Latvia’s state independence. The assembly gave the newly elected Supreme Council a powerful political mandate to adopt the Declaration of Independence.

The assembly took place while Soviet occupation still continued, when restoring independence was a politically and legally risky step. Its vote became one of the moral and political foundations of the 4 May Declaration.