Led Zeppelin released the album Led Zeppelin II in 1970 .
Although the group was initially unpopular with critics , they achieved significant commercial success with albums such as Led Zeppelin , 1969 , Led Zeppelin II , 1970 , Led Zeppelin III , 1970 , Led Zeppelin IV , 1971 , Houses of the Holy , 1973 , and Physical Graffiti , 1975 .
Led Zeppelin