Stefano Pioli has become the latest head coach to lead both Inter and city rivals AC Milan.
Former Inter boss Pioli joins an exclusive club after replacing Marco Giampaolo at Milan, who finally lost faith just seven Serie A games into his tenure.
Pioli is no stranger to San Siro, having spent a season on the blue side of Milan in 2016-17.
Inter had won 12 of their first 16 Serie A matches under Pioli before a run of five losses and two draws prior to his sacking in May two years ago.
As Pioli prepares to take the reins amid backlash from Milan fans and the hashtag "#PioliOut", we look at the coaches to have worked on both sides of the divide in a fierce rivalry dating back to 1909.
Viola was the first man to coach both Inter and Milan. Inter, then known as Societa Sportiva Ambrosiana, appointed the 32-year-old Hungarian for the 1928-29 season.
After three years at Atalanta, Viola made a switch to Milan for a brief stint in 1933-34. Known for his work as a player and a coach with Juventus, the one-cap Hungary international returned to the Rossoneri from 1939 to 1940.
A stalwart at Fiorentina, Bigogno left Florence for the red side of Milan in 1946. The Italian led Milan to a second-placed finish in 1947-48 prior to leaving a year later.
Bigogno's coaching career took him to Torino, Lazio and Udinese before ending up at Inter, where he only lasted half a season in 1958.
A member of Italy's 1962 World Cup squad, former Milan full-back Radice took charge of his boyhood club in 1981 after stints with Monza, Treviso, Cesena, Fiorentina, Cagliari, Torino and Bologna. Radice, who survived a car accident in 1979 which killed two men before passing away in 2018, was replaced by Italo Galbiati halfway through the season as Milan were eventually relegated.
Radice then joined Inter in 1983 - the Nerazzurri finished fourth in his sole season.
A rare exception, Castagner went straight from Milan to Inter. Castagner guided Milan to promotion at the end of the 1982-83 season, winning the Serie B title. However, he was sacked in March 1984.
Castagner quickly found his feet, crossing the divide to Inter, where he oversaw a third-placed finish in Serie A and runs to the semi-finals of the UEFA Cup and Coppa Italia. He was surprisingly replaced by Mario Corso in November 1985.
Having represented Milan as a player between 1959 and 71 - winning the Scudetto and European Cup twice, among other honours - Trapattoni began coaching the club at youth level. Considered the most successful club coach in Serie A history, he was named caretaker for a brief spell in 1974, later serving as first team coach.
After six Serie A titles with Juventus, Trapattoni controversially returned to San Siro but as Inter boss from 1986 to 1991. During his time at Inter, he won the Scudetto (1988-89), Supercoppa Italiana (1989) and UEFA Cup (1990-91).
Milan went from Fabio Capello to Zaccheroni in 1998. The new man made an immediate impact, winning Serie A by one point ahead of Lazio in his first season at the helm. Almost two campaigns followed before Zaccheroni was sacked in March 2001.
Inter turned to him in the middle of the 2003-04 season following Hector Cuper's exit. Despite guiding Inter to fourth place and securing Champions League qualification, Zaccheroni's tenure was brief as president Massimo Moratti replaced him with Roberto Mancini.
Now sporting director of Ligue 1 champions Paris Saint-Germain, Leonardo was the last coach to represent both Milan and Inter.
A member of the Milan squad that won the 1998-99 Scudetto, the Brazilian was tasked with following in the footsteps of successful coach Carlo Ancelotti, who left for Chelsea in 2009, despite lacking the required coaching badges. Stepping up from his role as technical director, Leonardo's start to life as coach was difficult following a shock 4-0 loss to Inter. Results showed signs of improvement but Leonardo eventually departed by mutual agreement at season's end.
In December 2010, Leonardo replaced Rafael Benitez at Inter on an 18-month contract. He set a Serie A record by collecting 33 points in 13 games and oversaw a memorable Champions League win over Bayern Munich. However, Leonardo - who ended his spell with Coppa Italia glory - eventually resigned in June after the club's failed title bid.