(ROME) — European Union leaders marked the 60th anniversary of their founding treaty on Saturday as a turning point in their history in the knowledge that Britain will officially trigger divorce proceedings from the bloc next week. Desperately trying to portray that sustained unity is the only way ahead in a globalized world, the no-show of British Prime Minister Theresa May was a symbol of the cathartic crisis the 27 other EU nations are going through. European Commission President Jean-Claude Juncker called Brexit “a tragedy.” EU Council President Donald Tusk said that sustained unity for was the only way for the EU to survive. “Europe as a political entity will either be united, or will not be at all,” he told EU leaders at a solemn session in precisely the same ornate hall on the ancient Capitoline Hill where the Treaty of Rome founding the EU was signed on March 25, 1957. “Only a united Europe can be a sovereign Europe in relation to the rest of the world,” Tusk said.