The Schuman Declaration of 1950 although he didn't speak of a European Union.

"Pronouncement" means solemn declarations as well as "Proclamation" and "Announcement".

The Laeken Declaration was a commitment by the European Union to be more democratic and transparent. This included themes such as division and definition of powers, setup of a European Constitution, and simplification of treaties.

The Laeken Declaration attempted to list the issues that needed discussion and resolution. This was in response to the Treaty of Nice.

A solemn promise is often referred to as an oath. It is a formal declaration or promise typically made with a strong sense of responsibility or commitment.