President Mattarella and his Portuguese counterpart, Marcelo Rebelo, had previously met in May 2016 when the Portuguese president also made a two-day official visit to Italy.
Sergio Mattarella’s visit started on Wednesday morning with a reception by Marcelo Rebelo de Sousa, with military honours followed by placing a wreath on the tomb of Luís Vaz de Camões, in Jerónimos monastery.
The two presidents met later once again at Belém palace, before Mattarella headed off to lunch with the Prime Minister, António Costa.
On Thursday, Sergio Mattarella was in Porto where he was welcomed at the City Hall.
Later, he was awarded an honourary doctorate degree by Porto University at a ceremony that Marcelo Rebelo de Sousa also attended.