Complex sentence: It was Herodotus who first used the ethnonym Getae; in Greek and Latin, in the writings of Caesar, Strabo and Pliny the Elder, this people becomes "the Dacians".
Split into simpler sentences: It was Herodotus who first used the ethnonym Getae. In Greek and Latin, in the writings of Caesar, Strabo and Pliny the Elder, the people became known as "the Dacians".