Porto's biggest rivalries are with the other Big Three members and regular league title contenders, Benfica and Sporting CP. They stem from the historical, political, economical and cultural clash between the cities of Porto and Lisbon, where the other two clubs are based. These rivalries became more intense in the past decades, particularly since Pinto da Costa assumed Porto's presidency in 1982 and adopted a regionalistic and confrontational speech towards Lisbon. In the following years, the club began establishing its dominance in Portuguese football, at the expense of Benfica and Sporting, who had been the traditional powers since the 1940s.