Answer by taking a quote from the following article:

The Kinks were an English rock band formed in Muswell Hill, North London, in 1964 by brothers Ray and Dave Davies. They are regarded as one of the most important and influential rock bands of the 1960s. The band emerged during the height of British rhythm and blues and Merseybeat, and were briefly part of the British Invasion of the United States until their touring ban in 1965. Their third single, the Ray Davies-penned "You Really Got Me", became an international hit, topping the charts in the United Kingdom and reaching the Top 10 in the United States.

In 1973, Ray Davies dived headlong into the theatrical style, beginning with the rock opera Preservation, a sprawling chronicle of social revolution, and a more ambitious outgrowth of the earlier Village Green Preservation Society ethos. In conjunction with the Preservation project, the Kinks' line-up was expanded to include a horn section and female backup singers, essentially reconfiguring the group as a theatrical troupe. Ray Davies' marital problems during this period began to affect the band adversely, particularly after his wife, Rasa, took their children and left him in June 1973. Davies became depressed; during a July gig at White City Stadium he told the audience he was "fucking sick of the whole thing", and was retiring. He subsequently collapsed after a drug overdose and was taken to hospital. With Ray Davies in a seemingly critical condition, plans were discussed for Dave to continue as frontman in a worst-case scenario. Ray recovered from his illness as well as his depression, but throughout the remainder of the Kinks' theatrical incarnation the band's output remained uneven, and their already fading popularity declined even more. John Dalton later commented that when Davies "decided to work again ... I don't think he was totally better, and he's been a different person ever since." Preservation Act 1 (1973) and Preservation Act 2 (1974) received generally poor reviews. The story on the albums involved an anti-hero called Mr Flash, and his rival and enemy Mr Black (played by Dave Davies during live shows), an ultra-purist and corporatist. Preservation Act 2 was the first album recorded at Konk Studio; from this point forward, virtually every Kinks studio recording was produced by Ray Davies at Konk. The band embarked on an ambitious US tour throughout late 1974, adapting the Preservation story for stage. Musicologist Eric Weisbard: "[Ray] Davies expanded the Kinks into a road troupe of perhaps a dozen costumed actors, singers and horn players. ... Smoother and tighter than on record, Preservation live proved funnier as well." Davies began another project for Granada Television, a musical called Starmaker. After a broadcast with Ray Davies in the starring role and the Kinks as both back-up band and ancillary characters, the project eventually morphed into the concept album The Kinks Present a Soap Opera, released in May 1975, in which Ray Davies fantasised about what would happen if a rock star traded places with a "normal Norman" and took a 9-5 job. In August 1975, the Kinks recorded their final theatrical work, Schoolboys in Disgrace, a backstory biography of Preservation's Mr Flash. The record was a modest success, peaking at number 45 on the Billboard charts. Following the termination of their contract with RCA, the Kinks signed with Arista Records in 1976. The song "Father Christmas" has remained a popular track. Driven by session drummer Henry Spinetti's drumming and Dave Davies' heavy guitar the song "Father Christmas" has become a classic seasonal favorite on mainstream radio. With the encouragement of Arista's management they stripped back down to a five-man core group and were reborn as an arena rock band. CANNOTANSWER

What year did Theatrcal incarnation start?

In 1973, Ray Davies dived headlong into the theatrical style,