Trafalgar Square Authority in conjunction with the charity Unicef, who began ticketing the event to control crowd numbers. A Christmas ceremony has been held in the square every year since 1947. A Norway spruce (or sometimes a fir) is presented by Norway's capital city, Oslo as London's Christmas tree, a token of gratitude for Britain's support during World War II. (Besides war-time support, Norway's Prince Olav and the country's government lived in exile in London throughout the war.) The Christmas tree is decorated with lights that are switched on at a seasonal ceremony. It is usually held twelve days before Christmas Day.
Christmas tree Christmas trees are variously erected on days such as the first day of Advent or even as late as Christmas Eve depending on the country; customs of the same faith hold that the two traditional days when Christmas decorations, such as the Christmas tree, are removed are Twelfth Night and, if they are not taken down on that day, Candlemas, the latter of which ends the Christmas-Epiphany season in some denominations. The Christmas tree is sometimes compared with the "Yule-tree", especially in discussions of its folkloric origins. Modern Christmas trees originated during the Renaissance of early modern Germany. Its 16th-century