day Mazzolini took them to see Mussolini, who promised to contact the German authorities and intervene in favour of San Marino's request. San Marino was a refuge for over civilians who sought safety on the passing of Allied forces over the Gothic Line during the Battle of Rimini, an enormous effort of relief by the inhabitants of a country that at that time counted only 15,000 people. Despite all this, Germany invaded San Marino on 13 September 1944. The Germans and Allies clashed on San Marino's soil from 17 September to 20 September at the Battle of San Marino; Allied troops occupied San Marino after that, but only stayed for two months before returning the Republic's sovereignty. Post-War period and modern times After the war, San Marino became one of the first countries in Western Europe to be ruled by a communist party (the Sammarinese Communist Party, in coalition with the Sammarinese Socialist Party) through democratic elections. The coalition lasted from 1945 to 1957, when the fatti di Rovereta occurred. This was one of the first times anywhere in the world that a communist government was democratically elected into power. The Sammarinese Communist Party peacefully dissolved in 1990 and restructured as the Sammarinese Democratic Progressive Party replacing the former hammer-and-sickle logo (a communist motif representing the rights of workers) with the image of a drawing of a dove by Pablo Picasso. Universal suffrage was achieved by San Marino in 1960. Having joined the Council of Europe as a full member in 1988, San Marino held the rotating chair of the organisation during the first half of 1990. San Marino became a member of the United Nations in 1992. In 2002 it signed a treaty with the OECD, agreeing to greater transparency in banking and taxation matters to help combat tax evasion. The SARS-CoV-2 virus, a cause of the COVID-19 pandemic, was confirmed to have reached San Marino in February 2020. As of June 2020, San Marino had the highest death rate per capita of any country, due to the effects of the COVID-19 pandemic. In April 2021, the nation received headlines for using the Russian Sputnik V COVID-19 vaccine rather than vaccines approved by the EU following a slow rollout for the latter vaccines. At the 2020 Summer Olympics, San Marino became the smallest country to earn a medal, as Alessandra Perilli and Gian Marco Berti won silver in the