Question: Name the English rock band formed in London who achieved international acclaim with their progressive and psychedelic music and who were a significant influence on the German progressive rock band Sylvan alongside Marillion and Genesis?
Sentence (from "Sylvan (band)"): Sylvan is a German progressive rock band, with some hard rock moments, and some melodic pop-rock elements, showing influences of psychedelic rock, Pink Floyd, Marillion, and Genesis.
Relevant evidence: Yes