input: John Power was previously the bass player, backing vocalist and only constant member along with Lee Mavers in The La's. He left the band on 13 December 1991 after becoming frustrated with the ever-increasing number of aborted studio sessions, having played essentially the same set of songs since 1986 and emerging as a songwriter in his own right. Power later commented that by that point he was more interested in his own songs "than anyone else's".  Having switched from bass to rhythm guitar whilst residing at Brucklay House - a near derelict squat in Mossley Hill, where the seeds of legendary dance label 3 Beat Records were sown, Power began jamming with friends and with an ever-changing line-up began to form Cast. The first addition to the band was ex-Shack bassist Peter Wilkinson who had seen Power performing acoustically at a free festival in Liverpool, and who Power had seen around town.". Embryonic lineups of the band, featuring several guitarists including Ged Malley, ex-La's members Barry Sutton and Cammy and drummer Russell Brady started gigging in mid 1992 and supported the likes of Pele and The Stairs. Power would later state that he was never happy with these lineups. Unhappy with the band and the demos recorded with Who sound engineer Bob Pridden, he split the band up and extricated himself from his Go! Discs contract in Summer 1993, with whom he was still signed to following his departure from The La's and set about forming a new lineup with Wilkinson.  The first new member to be recruited was Keith O'Neill who had previously played in The Empty Hours, The Windmills and Tommy Scott's pre-Space band The Australians and who Power had seen playing in local band The Windmills, fronted by Howie Payne later of The Stands and then guitarist Liam 'Skin' Tyson, who Wilkinson knew from college and had previously played in Pyramid Dream. When approached to join the band, Tyson initially declined as he had sold all of his musical equipment to teach canoeing at an outdoor centre in Alston in Cumbria. Tyson, who witnessed one of the band's early London shows and commented that "John had these songs, but not the band", joined the band in November 1993 and the new lineup played their first gig in Hull in January 1994. Within months the band secured high-profile support slots with Elvis Costello on two UK tours, including 2 nights at the Royal Albert Hall and Oasis. It was during the tour with Oasis that Polydor head of A&R Paul Adam, surprised that the band had not already been snapped up, approached the band to sign them. The band signed to Polydor on 13 December 1994, three years to the day that Power left The La's.

Answer this question "did they write their songs?"
output: Power later commented that by that point he was more interested in his own songs

input: In the lead-up to the album's release, a series of teaser advertisements depicting each symbol was placed in the music press. The album was a massive instant seller. It entered the UK chart at No. 10, rising to No.1 the following week and stayed on the chart for 90 weeks. In the US it stayed on the charts longer than any other Led Zeppelin album and became the biggest selling album in the US not to top the charts (peaking at #2). "Ultimately," writes Lewis, "the fourth Zeppelin album would be the most durable seller in their catalogue and the most impressive critical and commercial success of their career". At one point, it was ranked as one of the top five best-selling albums of all time.  Led Zeppelin IV received overwhelming praise from critics. In a contemporary review for Rolling Stone, Lenny Kaye called it the band's "most consistently good" album yet and praised the diversity of the songs: "out of eight cuts, there isn't one that steps on another's toes, that tries to do too much all at once." Billboard magazine called it a "powerhouse album" that has the commercial potential of the band's previous three albums.  Robert Christgau originally gave Led Zeppelin IV a lukewarm review in The Village Voice, but later called the album a "genre masterpiece", and wrote that it showed the band at the pinnacle of their songwriting. Even though he found their Medieval ideas limiting as usual, he said that it is "the definitive Led Zeppelin and hence heavy metal album". In his review for AllMusic, Stephen Thomas Erlewine credited the album for "defining not only Led Zeppelin but the sound and style of '70s hard rock", while "encompassing heavy metal, folk, pure rock & roll, and blues". In his album guide to heavy metal, Spin magazine's Joe Gross cited Led Zeppelin IV as a "monolithic cornerstone". BBC Music's Daryl Easlea said that the album made the band a global success and effectively combined their third album's folk ideas with their second album's hard rock style, while Katherine Flynn and Julian Ring of Consequence of Sound felt it featured their debut's blues rock, along with the other styles from their second and third albums. Led Zeppelin's Rock Hall biography described the album as "a fully realized hybrid of the folk and hard-rock directions". Music journalist Chuck Eddy named it the number one metal album of all time in his 1991 book Stairway to Hell: The 500 Best Heavy Metal Albums in the Universe.

Answer this question "What did some of the positive reviews say?"
output:
but later called the album a "genre masterpiece", and wrote that it showed the band at the pinnacle of their songwriting.