Development of an SPG on the chassis of the Pz.Kpfw. VIB Tiger II started in 1942. The project called for designing a common self-propelled gun carriage for the 17 cm Kanone 72 gun and 21 cm Mörser 18/1 howitzer. The concept of the SPG allowed the use of artillery systems from both the carriage and the ground. Work on building an experimental prototype began in 1945.