Evert's brother, Gerrit Zoudenbalch, had married Geertruida van Zuylen van Natewisch, daughter of Johan van Zuylen van Natewish, Lord of Natewisch and Zuylenstein, (died 1497). This Johan was at one time Mayor of Utrecht and a key supporter of Gijsbrecht's bid for the bishopric. Johan was a principal figure amongst the nobles and clergy who swore fealty to Gijsbrecht at Rhenen on 9 April 1456 four months prior to the Burgundian coup. Although Johan later reconciled himself with the Burgundian party and at one time acted as Councillor to David of Burgundy (he was cited as such in 1459), this alliance between the Zoudenbalchs and the Zuylen van Natewisches pre-figured and certainly influenced Gerrit's key anti-Burgundian stance in the Utrecht Civil War over twenty years later.