https://lego-x.com/2020/02/22/a-brief-history-of-the-creation-of-the-lego-constructor/
In 1932, carpenter Ole Kirk Christiansen founded his company in Billund, Denmark with the goal of promoting inventive play and awe-inspiring in children. At first, he made stepladders, however the effects of Great Depression forced him to be flexible and modify his business model. He changed his focus on manufacturing toys, and in doing so he developed one of the most loved brands in the history of the world.
Christiansen was a thinker who was progressive and quick to embrace new materials and technologies. In 1947, he was the first company to purchase a plastics injection molding machine in the world. This significantly increased the capabilities and range of Lego products. The machine also allowed him to experiment with a design that would later become the iconic Lego brick. The bricks came with pegs at the top and hollow bottoms that were interlocked with each one another, allowing children to build complex structures that went beyond the ones that could be constructed with wooden blocks of earlier generations.
The 1950s were a period of expansion for the company. Godtfred Kirk Christiansen’s daughter Kjeld Kirk Kristiansen joined the managerial staff and she began to modernize the manufacturing processes of the company. The expansion included the launch a line dollhouses, furnishings and individual Minifigures. In 1979 the company expanded into space with sets featuring astronaut minifigures, rockets lunar rovers and spaceships and also into the medieval realm with a Castle theme.
In 1990, the company introduced three Model Team Sets that were designed for advanced builder. These sets included small parts like gears, axles, and levers. They also offered an amount of realisticity and precision that was unheard of in the Lego series at the time.