Hearts have made four new signings, including Spanish playmaker Ruben Palazuelos, who has won a four-year contract after leaving Gimnastic.
Palazuelos played as a trialist for Hearts during pre-season
Striker Ricardas Beniusis and winger Andrius Ksanavicius have joined on year-long loans from Kaunas.
Slovenia Under-17 captain Matej Rapnik has penned a two-year agreement.
Palazuelos, who bought himself out of his contract with Gimnastic, said: "Hearts are a big club and I want to bring success to them."
The 24-year-old midfielder did enough to impress as a trialist in Saturday's friendly against Barcelona at Murrayfield.
"I am delighted to have joined Hearts," he told the club's website.
I have been impressed with everything I have seen at Hearts
"I was in Austria and Germany for the pre-season training camps and was impressed with the quality of the squad here.
"The Barcelona game was a great experience and hopefully I can help Hearts have more big European occasions while I am here."
Palazuelos had been on loan last season to Greek outfit Aris Thessaloniki and paid for his own release from Spanish outfit Gimnastic.
Beniusis is the latest to arrive on loan from Kaunas, who are sponsored by Hearts majority shareholder Vladimir Romanov's bank.
The 27-year-old striker moving to Tynecastle after the Lithuanians failed to reach the second qualifying round in the Champions League.
Beniusis, who has 18 caps for Lithuania, scored against Zeta last week but could not prevent a 5-4 aggregate defeat.
He and left winger Ksanavicius, a 30-year-old international, played as a trialist against Barcelona.
Rapnik, a left-sided centre-half, will be included in Hearts' under-19 squad this season after impressing on a week's trial last year.
The 17-year-old said: "It was a difficult decision to leave my family behind in Slovenia, but I believe this is the right move for me as I try to improve as a footballer.
"I have been impressed with everything I have seen at Hearts and I'm looking forward to my career at Tynecastle."
Midfielders Laryea Kingston and Michael Stewart signed for Hearts earlier in the summer.