On 11 April 1241 the army of the Kingdom of Hungary was destroyed by the Mongols at the river Slaná — the Sajó, in what is now northern Hungary. Among the survivors was Ondrej, son of that same Ivanka; his family later told the story that he had saved King Béla IV's life during the retreat. What is certain is what followed, and it followed all over the kingdom: Béla IV came home convinced that earth ramparts and timber palisades were worthless, and pressed his nobles to build in stone on high ground. Gýmeš is one of the castles that came out of that decision. It was not destroyed by the Mongols — in 1241 it did not yet exist.11. apríla 1241 Mongoli pri rieke Slaná rozdrvili vojsko Uhorského kráľovstva. Medzi tými, čo prežili, bol aj Ondrej, Ivankov syn; rodová tradícia hovorí, že na ústupe zachránil život kráľovi Belovi IV. Isté je to, čo nasledovalo, a nasledovalo to v celom kráľovstve: Belo IV. sa vrátil s presvedčením, že hlinené valy a drevené palisády nie sú na nič, a začal tlačiť na šľachtu, aby stavala z kameňa a na kopcoch. Gýmeš je jedným z hradov, ktoré z tohto rozhodnutia vzišli. Mongoli ho nezrovnali so zemou — v roku 1241 ešte neexistoval.
