Original: Güyük Khan is enthroned as the 3rd Great Khan of the Mongol Empire (an event also witnessed by a papal mission under Giovanni da Pian del Carpine) at Karakorum.
Simplified: Güyük Khan is enthroned as the 3rd Great Khan of the Mongol Empire. A papal mission under Giovanni da Pian del Carpine arrives at Karakorum and witnesses this event.