The Eurovision Song Contest 1973 was the eighteenth edition of the contest, organised by CLT and held on 7 April 1973 at the Nouveau Théâtre in Luxembourg City, Luxembourg. made its first appearance, becoming the first non-European nation to enter the contest, while Austria and Malta both withdrew, bringing the total participating nations to 17. Coming less than a year after the Munich massacre, security was unusually tight in light of Israel's debut, with the venue sealed off by the authorities and the Israeli delegation being isolated in their hotel and surrounded by armed guards when not required at the venue; the audience had also been warned not to stand during the show at the risk of being shot. This year marked the first abolition of the language rule, allowing participants the freedom to choose the language in which they wished to perform: several countries capitalised on this, with Finland and Sweden performing in English, while Norway performed in both English and French. Pre-recorded backing tracks were also permitted for the first time, however all vocals were still required to be performed live and any instruments featured on the track had to be seen on stage. Luxembourg won the contest for the second year in a row, with the French singer Anne-Marie David giving Luxembourg its fourth win with "Tu te reconnaîtras"; Luxembourg thus became the first country to win two outright back-to-back victories, Spain having won in both 1968 and 1969 but sharing the latter title.