The name evolved during the Middle Ages from Gallaecia, sometimes written Galletia, to Gallicia. In the 13th century, with the written emergence of the Galician language, Galiza became the most usual written form of the name of the country, being replaced during the 15th and 16th centuries by the current form, Galicia, which coincides with the Castilian Spanish name. The historical denomination Galiza became popular again during the end of the 19th and the first three-quarters of the 20th century, being still used with some frequency today, although not by the Xunta de Galicia, the local devolved government. The Royal Galician Academy, the institution responsible for regulating the Galician language, whilst recognizing it as a legitimate current denomination, has stated that the only official name of the country is Galicia.
When did it get its modern spelling?
15th and 16th centuries