Chelsea are one of the most successful clubs in the English top flight. Although they haven't won the league title since 2017, they have finished in the top four and made plenty of big signings to bolster their roster.The Blues have regularly looked to Serie A for new signings over the years, and have signed more than 20 players from the Italian top division in the Premier League era. They have reportedly launched a bid to re-sign Romelu Lukaku, and are prepared to break their transfer record for the Inter Milan forward.✅ £95m fee.✅ £12m a year wages (£230k per week)Romelu Lukaku to Chelsea… 🔜🔵 pic.twitter.com/4d1a2u6rRP— LDN (@LDNFootbalI) August 5, 2021Lukaku has been in brilliant form since joining Inter Milan from Manchester United in 2019. The Belgian forward has scored 64 goals in 95 appearances for the Nerazzurri and was named the Serie A's Most Valuable Player in the club's Scudetto-winning campaign last season.As the Blues look to make Lukaku their lastest import from the Serie A, here's a look at the five best signings made by Chelsea from the Italian top flight over the years:#5 Marcel DesaillyMarcel Desailly was one of the most high-profile signings made by Chelsea.Marcel Desailly was one of the most high-profile signings made by Chelsea during the 1990s. The French international signed for the Blues from AC Milan in 1998, weeks before winning the FIFA World Cup, and his arrival seemingly kickstarted the club's upward trajectory.Desailly was a two-time European champion when he arrived at the club and was the first to win the title with different clubs in consecutive seasons.Nicknamed 'The Rock', the World Cup winner was not only powerful in central defence but also displayed admirable quality on the ball. Desailly helped Chelsea qualify for the Champions League for the first time and also lifted the UEFA Super Cup in his debut season at the club.He won the FA Cup with Chelsea in 2000 and followed that up weeks later by winning the European Championships with France."The speed, the attitude and the crowd was totally different to what I had experienced. When we reached the Champions League, it was a great experience to see the emotion of the people. For me it was normal and amazing at the same time," said Marcel Desailly.Desailly became the Chelsea captain and took young John Terry under his wing, helping the Englishman evolve into a solid presence in the Chelsea back four. Terry succeeded Desailly as club captain when the French international departed the club in 2004.#4 Gianluca VialliGianluca Vialli was one of the many signings who followed Ruud Gullit to Chelsea.There were plenty of players who arrived at Chelsea from Serie A after Ruud Gullit's appointment as player-manager; Gianluca Vialli was one of them. Vialli arrived at Stamford Bridge in 1996 after leading Juventus to the Champions League title.Vialli adapted quickly to the demands of English football and scored 11 goals in all competitions as Chelsea won the FA Cup in his debut season. His strength and hold-up play were impressive as was his shooting accuracy with either foot; he also had a knack of catching opponents off-guard with his early shots.Gianluca Vialli became a 🔵, #OnThisDay 25 years agoHe made a big impact as a @ChelseaFC player and manager pic.twitter.com/oiymVKSdM2— Premier League (@premierleague) May 24, 2021in 1998, Vialli took over from Gullit as Chelsea's player-manager, leading the Blues to League Cup and Cup Winner’s Cup success, followed by the UEFA Super Cup win with a victory over Real Madrid.Vialli scored 40 goals in 88 appearances for Chelsea across competitions during his playing time at the club, also helping them qualify for the Champions League for the first time in their history in 1999-2000.He ended his managerial spell at the Blues after lifting the FA Cup with a win over Aston Villa, making him the club’s most successful manager at the time, as well as a much-loved player.