Aside from Fairport Convention, Steeleye Span was the most successful and enduring British folk-rock band. The parallels between the bands are numerous: both updated traditional British folk material with rock arrangements, both featured an excellent female lead singer (Sandy Denny for Fairport, Maddy Prior for Steeleye Span), both frequently employed multi-part harmonies, and both mixed original and traditional songs. Although Fairport was more innovative in its early days, Steeleye Span was arguably the more interesting band after 1970, when personnel changes had gutted the original Fairport lineup. Steeleye Span, too, would undergo numerous personnel changes even at their peak. Prior was the constant factor that gave the group something of a recognizable identity at all phases of their journey.
One thing that differentiated Steeleye Span from their counterparts was that Fairport came to traditional folk from a rock background, whereas Steeleye traveled in the opposite direction. The impetus for Steeleye Span's formation, ironically, came from ex-Fairport Convention bassist Ashley Hutchings. Hutchings wanted to keep pursuing the traditional folk direction ploughed by Fairport on the 1969 album Liege and Lief, and left Fairport to joined forces with Prior, Hart, Terry Woods, and Gay Woods (Terry's wife) to anchor the first incarnation of Steeleye Span.
This lineup only lasted for one album, with the Woods leaving for Doctor Strangely Strange; Terry Woods would eventually resurface with the Pogues in the 1980s. He was replaced by Martin Carthy, one of the most respected guitarists on the English folk circuit. Carthy's abdication of acoustic folk for electric (if drum-less) folk-rock apparently caused much consternation within the purist English folk community, a kerfuffle that is hard to understand (at least from an American perspective), given that Dylan had already successfully fought that battle in the mid-'60s. While Steeleye Span played folk music, they had no aversion to playing it loud, and this version of the band proved that it was possible to create an energetic ruckus without a drummer.
Both Hutchings and Carthy, by far the most famous members of the group, left around the end of 1971. This sort of defection would have crippled most acts. Yet Steeleye Span not only persevered, but entered their most commercially successful phase. Tim Hart was once quoted as saying that the group wanted to "put traditional music back into current musical language -- to make folk music less esoteric." They were aided in doing so by new bassist Rick Kemp, who became Maddy Prior's husband. In 1973, they finally added drums to the band, becoming a true folk-rock act after years of ramping up.
One asset to Steeleye Span's unusual durability (in the face of the revolving door of players) was their open-minded approach to contemporary influences. They covered oldies (and well) by Buddy Holly, the Four Seasons, and Phil Spector. David Bowie and Peter Sellers made cameo appearances on their albums in the mid-'70s.