Lusitanic definitions of "Lusitanic" or "Lusitanian" may include medieval-to-modern Galicia, because the Portuguese people and Galician people share close linguistic and cultural ties, including pre-Roman Celtic ones. Modern Portuguese and the Galician language both derive from medieval Galician-Portuguese, and the term is a cultural classification more than a historic–geographical definition. Although, in Ancient Roman times, the Gallaeci were not part of Lusitania province, what became the Galician-Portuguese language developed from Vulgar Latin in Gallaecia, which comprised what is now Galicia, as well as north Portugal, the center of the development of post-Roman Portuguese culture. Later Portuguese use of the name "Lusitania"
Lusitania from the Greek λυσσα, "frenzy" or "rage", and sometimes Rage personified; for later poets, Lusus and Lyssa become flesh-and-blood companions (even children) of Bacchus. Luís de Camões' epic "Os Lusíadas" (1572), which portrays Lusus as the founder of Lusitania, extends these ideas, which have no connection with modern etymology. In his work, "Geography", the classical geographer Strabo (died ca. 24 AD) suggests a change had occurred in the use of the name "Lusitanian". He mentions a group who had once been called "Lusitanians" living north of the Douro river but were called in his day "Callacans". The Lusitani, who were