Complex sentence: The period of Didone types'greatest popularity coincided with the rapid spread of printed posters and commercial ephemera and the arrival of bold type and many Didone types are among the earliest types designed for' display' use.
Split into simpler sentences: The period of Didone types'greatest popularity coincided with the rapid spread of printed posters and commercial ephemera and the arrival of bold type. As a result, many Didone types are among the earliest types designed for' display' use.