A distinctive feature of the period is the proliferation of distinct genres of paintings, with the majority of artists producing the bulk of their work within one of these. The full development of this specialization is seen from the late 1620s, and the period from then until the French invasion of 1672 is the core of Golden Age painting. Artists would spend most of their careers painting only portraits, genre scenes, landscapes, seascapes and ships, or still lifes, and often a particular sub-type within these categories. Many of these types of subject were new in Western painting, and the way the Dutch painted them in this period was decisive for their future development.