The purpose of the event, whose slogan is "Make Europe great again", is to show strength towards the EU and ideological community with President Trump, primarily when it comes to migration.
A proposal for the defense of "national sovereignty and European freedom and identity" will be presented, according to the organizing Spanish right-wing populist party Vox.
At the same time, some of Trump's proposals, such as the tariff threat against the EU or the talk of taking over Greenland, may lead to tensions within Europe's far-right. The leader of France's National Rally, Jordan Bardella, has recently said that the fact that one likes Trump's "patriotism" does not mean that one "wants to become a vassal for the USA".
Hungary's Prime Minister Viktor Orbán, French far-right politician Marine Le Pen, the Netherlands' Geert Wilders, and Italy's Vice Prime Minister Matteo Salvini are some of the participants in Madrid.
Patriots for Europe (PFE), which gathers nationalist parties, is the third largest group in the EU Parliament.