CTT – Correios de Portugal, S.A. (lit. 'CTT – Post of Portugal') is a Portuguese company that operates as both the national postal service of Portugal and a commercial group with subsidiaries operating in banking, e-commerce, and other postal services. It was founded in 1520 by King Manuel I of Portugal, during the Portuguese Renaissance, and CTT is the oldest company still in operation in Portugal to this day. In 1991, CTT became a public limited company, and in December 2013 its shares were listed on Euronext Lisbon.