It is called 'Romanesque' style, dear @rosz and its architecture has nothing to do with a budget 😊 It has nothing to do with the Gothic either, as it was created and flourished before that style was invented. But personally I like Romanesque architecture a lot, much more than Gothic, and the Église Saint-Pierre-au-Parvis de Soissons is a great representative of it. That's truly a beautiful find! 😍
As for the development of architecture in Europe in ancient times, remember that Europe is called "the old continent". That says a lot. About everything 😊