Upon his return to power, Béla began rebuilding his country, including a massive construction campaign which produced the system of castles as a defense against the threat of a Mongol return.
Setelah kembali berkuasa, Béla mulai membangun kembali negaranya, termasuk sebuah kampanye pembangunan besar-besaran yang menghasilkan sistem istana sebagai pertahanan melawan ancaman kembalinya Mongol.