Barov is right, there was no Kingdom prior to settling present day Croatia and Christianiazation of Croats on present day soil. Prior to that Croats and White Croatia was more like territory of numerous White Croatian tribes (families) of Pagan Croats, rather then a Christian structure as kingdom or anything such. Also White Croatian borders weren't determined and official, rather these maps show where our Tribes lived across which territories according to archeology remains, history and folk sayings etc. For all we know remains of White Croats on present day Polish territory was lost and diminished due to losing a war to some Czech prince, and due to larger part of Croatian people left to settle Dalmatia/Pannonia.