Lazio began gearing up for the new Serie A campaign with the official announcement of three new signings on Wednesday.
The club had already made it known that they were on the verge of signing Serbian defender Dusan Basta, countryman Filip Djordjevic and Parma midfielder Marco Parolo, and now the deals have been rubber-stamped.
A statement on www.sslazio.it on Wednesday morning read: "SS Lazio announces that it has filed the contract of Filip Djordjevic."
A second statement then followed confirming the two further arrivals, saying: "SS Lazio announces that it has filed the contracts of Dusan Basta and Marco Parolo."
Parolo, who has signed a five-year contract, scored eight goals in 36 league appearances to help Parma finish sixth in Serie A last season.
The 29-year-old's strong performances earned him a place in Italy's World Cup squad and he featured in two games in Brazil.
Basta, 29, has signed a four-year deal after arriving from Udinese while 26-year-old striker Djordjevic moves to Rome on a free transfer after seven campaigns with French side Nantes.
Lazio president Claudio Lotito told Mediaset on Tuesday: "We intend to strengthen the team, the next stage will involve the defence.
"I hope that pundits and fans take note of this with satisfaction and leave their old attitudes and prejudices behind.
"Lazio need the support and affection of their fans."
Lazio finished in a disappointing ninth place last season and will be coached by Stefano Pioli during the 2014-15 campaign after Edy Reja resigned in June.