In contrast, the hypothesis of a Thraco-Dacian or Daco-Thracian branch of IE, indicating a close link between the Thracian and Dacian languages, has numerous adherents, including Russu 1967, Georg Solta 1980, Vraciu 1980, Crossland 1982, Rădulescu 1984, 1987. Mihailov (2008) and Trask 2000. The Daco-Thracian theory is ultimately based on the testimony of several Greco-Roman authors: most notably the Roman imperial-era historian and geographer Strabo, who states that the Dacians, Getae, Moesians and Thracians all spoke the same language. Herodotus states that "the Getae are the bravest and the most just amongst the Thracians", linking the Getae, and thus the Dacians, with the Thracians. Some scholars also see support for a close link between the Thracian and Dacian languages in the works of Cassius Dio, Trogus Pompeius, Appian and Pliny the Elder.