They all were very Catholic, the De lannoys, the Nassaus... as if they wanted to hear every word, to absorb every prayer but it was interesting that also the foreign royals were so active: the Prince of Asturias singing a French psalm out of the head, the protestant Queen of the Netherlands agreeing with closed eyes and in trance 'Ubi caritas et amor, Deus ibi est', the prayers and mass in German, Letzebuergisch, French, English, Dutch, Portuguese (Isabella, or was it in Spanish?), wonderful!
By the way, two of the priests in the wedding were family of the bride: the Abbot Vincent della Faille de Leverghem and the Brother Emmanuel della Faille de Leverghem.