Former European Investment Bank president, Philippe Maystadt, died on Thursday at the age of 69.
Belgian national, Maystadt, served as president of the bank in Luxembourg from 2000 to 2011.
Jean-Claude Juncker, President of the European Commission and former Luxembourgish Prime Minister, paid tribute to a "great European, a colleague and friend".
He described Maystadt as a "man of action and conviction" who acted as his "accomplice, companion, source of inspiration and model".
"Philippe Maystadt devoted a large part of his life to Europe, setting up the economic and monetary union and the euro," Juncker wrote.
Juncker stated they shared the same ambition for a "more social Europe" and said Maystadt developed the role and activities of the EIB during his leadership.
Current EIB president, Werner Hoyer, said Maystadt "transformed" the bank during his 12 years at the helm, making the EIB a "powerful tool for European economy".
"Philippe was a true European, one of those who could really claim to be the architect of the euro, but due to his modesty, never did claim this," he said. "He has left us but he will never be forgotten."
On Thursday afternoon, Belgian prime minister Charles Michel posted a tweet describing Maystadt as a "committed European who was close to and listened to citizens".
"A great man has left us," he added.
Before joining the EIB Maystadt worked in various positions within the Belgian government, including Deputy Prime Minister and Minister of Finance and Foreign Trade. He also chaired the Interim Committee of the International Monetary Fund.
He studied law and economics at the Catholic University of Louvain (UCL) and Los Angeles in the United States and later became professor at the UCL's faculty of law.
Maystadt was the EIB's sixth president, succeeding Sir Brian Unwin and preceeding current president, Werner Hoyer, who has been in the role since January 2012.