Testament is an American thrash metal band from Berkeley, California. Formed in 1983 under the name Legacy, the band's current lineup comprises guitarists Eric Peterson and Alex Skolnick, lead vocalist Chuck Billy, drummer Gene Hoglan, and bassist Steve Di Giorgio. Since its inception, Testament has had numerous lineup changes, leaving Peterson as the only constant member. Billy replaced original singer Steve "Zetro" Souza (who left the band to join Exodus as the replacement of Paul Baloff) in 1986, prior to the recording of their first studio album, The Legacy, and has been a member of the band since.

Testament's second album, The New Order, was released in May 1988, and found the band continuing in a similar vein. The album was a minor success, peaking at number 136 on the Billboard 200, and managed to sell over 250,000 copies. In support of The New Order, Testament opened for Megadeth on their So Far, So Good... So What! tour in Europe, and toured the United States with the likes of Death Angel, Vio-Lence and Raven. After touring in support of The New Order, the band headed back into the studio to record their third studio album Practice What You Preach. Released in August 1989, the album minimized the occult and gothic themes found in the lyrical content of their first two albums, instead focusing on real-life issues such as politics and corruption. Practice What You Preach performed better on the charts than The New Order, reaching at number 77 on the Billboard 200, and included the hit single, the title track, which saw extensive airplay on Headbangers Ball. Testament toured for nearly a year behind Practice What You Preach with several bands, including Annihilator, Wrathchild America, Mortal Sin, Nuclear Assault and Savatage. By 1990, the album had sold over 450,000 copies. In October 1990, Testament released their fourth studio album Souls of Black. Although reviews were mixed, the album managed to sell respectably, in no doubt largely off the strength of the single title track, and saw the band perform on arena tours, including the European Clash of the Titans tour with Megadeth, Slayer and Suicidal Tendencies. They also opened for Judas Priest on their Painkiller tour from October to December 1990, and Slayer on their Seasons in the Abyss tour from January to March 1991. Attempting to reconnect with an audience distracted by the growing grunge movement, Testament released The Ritual in 1992. The Ritual saw a stylistic move away from thrash to a slower, slightly more traditional heavy metal sound. The Ritual peaked at 55 on the Billboard Hot 100, the band's highest chart position at the time, and the power ballad "Return to Serenity" managed to receive radio airplay, peaking at number 22. In support of the album, Testament toured Europe and North America, headlining their own tours, as well as opening for Iron Maiden on their Fear of the Dark tour, and Black Sabbath on their Dehumanizer tour. However, the success of The Ritual did not put an end to the tensions within the band. As early as 2009, Testament commenced writing new material for their tenth album. In an interview with Metalheadz, guitarist Eric Peterson stated that there were about four songs written and that "there's other guys in the band who like to play the more rock melodic style but the next one is gonna be a bit heavier." In a January 2011 interview during the 70000 Tons of Metal cruise, frontman Chuck Billy revealed that Testament had been working on six new songs, with four or five "maybe left to write," and would begin recording their new album by early March. On 18 May 2011, guitarist Alex Skolnick posted an update on his Twitter, saying, "Another tune done! My riffs from last week [plus] some of [fellow Testament guitarist Eric Peterson's plus] new ones we wrote today. Planning one more, then we've got more than we need." Testament began recording their tenth studio album on June 20, 2011. Drummer Paul Bostaph was unable to take part in the recording due to a "serious injury", although he was expected to rejoin when the band tours to support the album. Gene Hoglan, who played drums on the band's 1997 album Demonic, filled in for Bostaph. It was also reported that Lamb of God drummer Chris Adler would make a special guest appearance on a couple of bonus tracks. Testament appeared at the California dates of the summer 2011 Rockstar Energy Drink Mayhem Festival, replacing In Flames. On 14 July 2011, it was announced that the tenth Testament studio album would be called Dark Roots of Earth, which, after many delays, was released on July 27, 2012. Dark Roots of Earth debuted at No. 12 on Billboard 200, the band's highest chart position to date. Prior to the album's release, the band toured in the fall of 2011 with Anthrax and Death Angel. Overkill was invited to the tour, but due to the pre-production of their sixteenth studio album The Electric Age, they did not participate. It was announced on 1 December 2011 that Paul Bostaph had left Testament. Gene Hoglan recorded the drum tracks for Dark Roots of Earth and continues to play live with the band. In interviews, Testament have expressed pleasure in Hoglan's playing, and hope that he would continue playing with the band for the foreseeable future. In August 2012, guitarist Eric Peterson stated that Testament would record an eleventh studio album if Dark Roots of Earth did well. A week prior to the release of Dark Roots of Earth, Billy promised that Testament would not take "huge gaps" between albums anymore, and would "work hard and tour for two years or so," and try to release another album when they could. Hoglan has also said that he would "absolutely dig" to be a part of the writing of the next Testament album. On 13 September 2013, Billy told Rock Overdose that from January to April 2014, Testament would be writing and recording their eleventh studio album for a 2014 release. Testament released a live DVD/double album Dark Roots of Thrash on 15 October 2013. The release documents the band's sold-out headlining performance at the Paramount in Huntington, New York, in February 2013. On 13 January 2014, it was announced that bassist Greg Christian had left Testament again, and Steve Di Giorgio returned to the band as his replacement; it was also announced that he would be involved in the making of the band's next album. Christian has explained that the reasons he had left Testament for the second time were because of money disputes and differences with the band. Asked about in an April 2015 interview about Testament's plans to begin recording their new album, Peterson said that his "main goal" was to "get home [from tour] in June, finish it up and get in the studio by September." Billy also said that the band's goal was to have the album finished by Thanksgiving. Slovenian bassist Tilen Hudrap (Pestilence, Vicious Rumors, Paradox, Thraw) and Bay Area drummer Alex Bent (Arkaik, Dragonlord, Decrepit Birth, Battlecross) filled in for Di Giorgio and Hoglan in August at the prestigious Canadian open air festival Heavy Montreal, attended by more than 70 000 spectators. In May 2016, Billy confirmed the album would be entitled Brotherhood of the Snake. Of the album's lyrical content, he commented, "The Brotherhood of the Snake was actually a society about 6,000 years ago that debarred all religions. It was just a fascinating topic that caught our eye and attention and spawned a lot of songs. We're going with that vibe. There will be some songs that deviate, but the majority will be around that and aliens and religion. Then I'll probably tap into my native heritage and write some songs about that. It's not just going to be one concept, but there is some interesting stuff that we're finding to write about." Brotherhood of the Snake was released on October 28, 2016, and received generally positive reviews from critics, and scored Testament their second-highest chart position on the Billboard 200, reaching at number twenty. Shortly after its release, Testament embarked on an international tour with Amon Amarth, and toured North America in April-May 2017 with Sepultura, Prong, Infernal Tenebra and Dying Gorgeous Lies. The band also toured Europe with Annihilator and Death Angel in November and December 2017, and again in March and April 2018, with Annihilator and Vader supporting. Along with Anthrax, Lamb of God, Behemoth and Napalm Death, Testament will open for Slayer on their final North American tour, which will take place in the spring and summer of 2018. CANNOTANSWER

Answer the following question by taking a quote from the article: What happened following this change in crew?

Christian has explained that the reasons he had left Testament for the second time were because of money disputes and differences with the band.