 Some are loosely connected thematically to the accompanying preludes.The ricercars all feature themes written in whole and half notes, the C major "Ricercar pro Festis Natalitys" being one notable exception with the theme composed mostly of quarter and eighth notes.Three are marked alla breve, "Ricercar pro Festis Natalitys" is in common time and the F major ricercar is in 3/2.