recorded parts of Lock Up the Wolves before Bain and Appice were replaced with Teddy Cook and former AC/DC drummer Simon Wright, respectively. The album was released on 15 May 1990, and the band embarked on a tour in support of the album. Lock Up the Wolves represented a clear evolution for Dio as a band. Ronnie James Dio replaced his band's entire line-up from its previous album, but only after working with them to some degree on what would eventually become Lock Up the Wolves. In this sense, the album was not an abrupt change from the band's previous work, but a protracted evolution in the band's sound that was ultimately delivered by one of the band's strongest line-ups. By 1990 and 1991 the music industry would go through a pretty dramatic shift as Grunge began to make a commercially aggressive appearance in the music scene: Soundgarden, Alice in Chains, Screaming Trees, had already been signed to major labels and had performed well commercially by then. Second album with Dio shelved Robertson's tenure in Dio was cut short by music industry persistence for a Ronnie James Dio reunion with Black Sabbath. In 1991 it was announced that the highly anticipated reunion would take place. At that time, the band, including Robertson, had been writing songs for an upcoming album that had been scheduled for a May 1991 release. Once a Black Sabbath reunion with Ronnie James Dio was announced, what would have been Robertson's second album with Dio was shelved. Robertson has confirmed the existence of rehearsal recordings for what would have been the follow-up to Lock Up the Wolves but he has stated these will remain archived and he does not feel comfortable releasing any of this to the public, maintaining he would have only done that with permission from Ronnie James Dio himself. Reunion with Ronnie James Dio unrealised A Robertson reunion with Dio, which many fans had hoped for did not materialise before the singer's health declined, and he died in May 2010. A reunion nearly took place in 2001 when Robertson was scheduled to replace Craig Goldy on tour in South Africa in support of Dio's then-new album Magica after Goldy suffered an injury. However the September 11 attacks affected the band's tour plans. A second stint for Robertson in Dio never materialised. After Dio (1991–present) When Dio was put on ice due to the