The man who spent 20 years as the United Nations' mediator in a name dispute between Greece and Macedonia says the Greek parliament's ratification of a reconciliation agreement "ushers in a new era for the consolidation of peace and security in the Balkans." Matthew Nimetz said the vote by lawmakers in Athens to endorse the deal also "opens the door to a new relationship" between the countries after the 27-year dispute over rights to the Macedonia name. Under the deal that Mr Nimetz helped negotiate, Macedonia will be renamed North Macedonia in return for Greece dropping objections to its membership in Nato and, eventually, the European Union. Macedonia's parliament approved constitutional changes to rename the country North Macedonia on January 11. Mr Nimetz was US President Bill Clinton's envoy in the mediation of the dispute for one and a half years and has been the UN secretary-general's representative on the issue since 1999. He says he looks forward to the completion of the process outlined in the agreement. The Greek parliament on Friday narrowly ratified the landmark deal, ending one of the world's longest diplomatic disputes and earning rich praise for the "historic" move. A total of 153 MPs in the 300-seat Greek parliament approved the name Republic of North Macedonia, despite widespread public opposition.<br/> Since 1991, Athens has objected to its neighbour being called Macedonia because Greece has a northern province of the same name. In ancient times it was the cradle of Alexander the Great's empire, a source of intense pride for Greeks. To make the UN-sponsored agreement final, Greece must now ratify a protocol approving Macedonia's membership of the Western military alliance Nato. This is expected to take place next month. "We warmly welcome the next crucial step in the ratification... taken with today's vote by the Hellenic Parliament," EU President Jean-Claude Juncker said in a joint statement with foreign policy chief Federica Mogherini and enlargement commissioner Johannes Hahn. "Both countries have seized this unique opportunity which sets an example of reconciliation for Europe as a whole and will give a further boost to the European perspective of the region," the EU officials said. UN Secretary-General Antonio Guterres offered his congratulations, saying in a statement that "the implementation of the agreement will strengthen peace and security in the region and provide a fresh impetus to reconciliation efforts in Europe and beyond.” Greek Prime Minister Alexis Tsipras, who forged a close relationship with North Macedonia counterpart Zoran Zaev in drafting the agreement last year, congratulated his counterpart adding, “Together with our peoples we reached a historic victory.” "Long live the Prespa Agreement! For eternal peace and progress of the Balkans and in Europe! "Today we write a new page for the Balkans. The hatred of nationalism, dispute and conflict will be replaced by friendship, peace and cooperation," Mr Tsipras said. European Council President Donald Tusk said the two countries had achieved "mission impossible." Germany – whose chancellor Angela Merkel had personally expressed gratitude to Mr Tsipras during a recent visit to Athens – also welcomed the news as a "victory for diplomacy." However, protests have been held in both countries against the agreement – some of them violent – and lawmakers in Greece have reported threats and arson attacks against their homes. A few dozen protesters gathered outside Greek parliament on Friday. A poll released by SKAI TV on Thursday night found 62 per cent of respondents oppose the deal, with 27 per cent in favour. A week earlier, another poll in Proto Thema weekly had found 66 per cent in opposition. Anti-Tsipras daily Ta Nea on Friday said the deal was the result of a "painful compromise" and was full of "pitfalls". In addition to normalising relations between the two countries, implementation of the agreement will open the door for Macedonia to join the European Union and Nato, hitherto blocked by Athens' veto. But in Greece, its neighbour's name continues to fuel controversy in politics and society, ahead of parliamentary elections scheduled for October. Critics say the agreement – which drops Greece's objections to an official Macedonian language and identity – opens the way for possible cultural usurpation and trade disputes. Main opposition leader Kyriakos Mitsotakis of the conservative New Democracy party said the agreement "creates new problems" and "awakens nationalism". "Your foreign policy is superficial and ignorant... you should be ashamed," he told the government. But Mr Tsipras told parliament during a two-day debate on the deal: "We never had a Macedonian language. Alexander the Great spoke Greek." "Are you afraid of a state that does not even have two percent of our [military] capability and not even 6 per cent of our economic output?" former foreign minister Nikos Kotzias, a signatory of the agreement, asked parliament on Thursday. On Sunday, clashes between police and masked protesters left 40 people injured as tens of thousands demonstrated in Athens against the name change. The government blamed far-right extremists and the neo-Nazi Golden Dawn party for the violence.