The language rule forcing countries to enter songs sung in any of their national languages was dropped , so performers from some countries sang in English . The event was marked by controversy when the Spanish song , " Eres tú " ( by Mocedades ) , was accused of plagiarism due to reasonable similarities in the melody with the Yugoslav entry from the 1966 contest ( " Brez besed " sung by Berta Ambrož ) ; however , " Eres tú " was not disqualified . After finishing second in the contest , the song went on to become a huge international hit
1966 contest
Eurovision Song Contest 1966
Eurovision Song Contest 1973