Renate Müller began designing and producing toys in the early 1960s as part of an endeavor launched by Helene Haeusler at the Sonneberg Technical College for Toy Design in Sonneberg, Germany. Haeusler wanted to produce large, bright, exceptionally made toy animals that could be used in a therapeutic setting for children. The toys were used for balance training and orthopedic exercise as well as for sensory exercises and hand-eye coordination.
Müller, trained in toy design and working as a designer for the H. Josef Leven Company, brought Haeusler's ideas into production. The toys debuted at the Leipzig Trade Fair in 1967 and continued annually. The toys were tested by psychiatric hospitals and clinics throughout Germany and proved hugely successful. Each year Müller added new animals and objects to the collection.
In 1990, Renate Müller took over the rights to her designs and continues to hand-produce very limited quantities of the classic designs as well as new designs.