Portuguese is the official language of which modern day country because they claimed it as a colony

Portuguese is the official language of Brazil, which was claimed as a colony by Portugal in the early 16th century.

The modern-day country for which Portuguese is the official language due to its colonial past is Brazil. Portugal claimed Brazil as a colony in the early 16th century and subsequently dominated the region for over three centuries until Brazil gained independence in 1822. As a result of this colonial history, Portuguese became the official language of Brazil.