Sunderland have confirmed the signings of Modibo Diakite, Valentin Roberge and Cabral on free transfers.
Diakite, 26, is the most high-profile addition after being brought in from Italian side Lazio.
The France-born player is joined by Maritimo defender Roberge, 26, and Basel midfielder Cabral, 24.
The trio - all signed on three-year contracts - arrive on Wearside as manager Paolo Di Canio reshapes the squad he inherited from Martin O'Neill.
The Italian had announced plans to bring in six players during the summer.
He made 88 appearances during an injury-plagued spell there, winning the Coppa Italia with the club in 2008-09.
Diakite could be partnered at the back by Roberge, who has arrived from Portuguese club Maritimo following time at Guingamp, Paris St-Germain and Greek club Aris.
Elsewhere, Cabral comes to Sunderland after winning the Swiss league title four times in six years with Basel.
The Cape Verde-born midfielder was on the bench for both legs of their Europa League semi-final defeat by Chelsea last season.
Di Canio has also added to his backroom staff in pre-season, bringing in Italian duo Roberto De Fanti and Valentino Angeloni as their new director of football and chief scout respectively.