In 1978 LEGO released 6 Duplo sets across 2 subthemes. The largest Duplo set from 1978 was
529 Animals with a piece count of 39.
The LEGO DUPLO theme was introduced as far back as 1969 and is designed for children ages 1 to 5. It features DUPLO figures which are much larger than minifigures and DUPLO blocks which are about twice the length, width, and height of a standard System brick. Like LEGO System, DUPLO also has subthemes that are often junior versions of System themes, like Pirates and Castle and licensed themes like Disney and Super Heros.
1978 LEGO Sets
In 1978, LEGO released several new sets and themes, including the LEGO City theme, which expanded upon the city sets released in previous years and introduced new models of public transportation such as buses and taxis.