Early dynamical world models: A historical review

Models of the universe, in the sense of solutions to the cosmological field equations, took their start in 1917 with Einstein’s closed universe. During the next two decades they were developed to comprise evolving models, some of them cyclic and some of them with a definite age. The history of this development, as it occurred up to the mid 1930s, is reviewed. It is argued that in 1930-31, cosmology experienced a kind of paradigm shift.