Here's a breakdown of the history:
* Roman Empire: When the Roman Empire conquered the Iberian Peninsula, Latin was introduced as the language of administration and commerce.
* Medieval Period: After the fall of the Roman Empire, Latin evolved into various regional languages, including Galician Portuguese.
* Portuguese Nation: As the Portuguese nation emerged and expanded its influence, Galician Portuguese evolved further, eventually becoming the language we know as Portuguese.
* Colonization: During the Age of Exploration, Portuguese was brought to other parts of the world through Portuguese colonization, leading to its spread to Brazil, Angola, Mozambique, and other countries.
Therefore, Portuguese is spoken in Portugal because it originated there and has been the official language of the country for centuries.