Planning for the Tiger II started as early as May 26th of 1941, a year before the Tiger I entered production, when Adolf Hitler met with officials responsible for the armament development including panzer development. By the fall of 1942/January 1943, designers at Porsche and Henschel started work on a new heavy tank that would eventually replace the Tiger I.
The first 50 King Tigers (including the three prototypes) were equipped with turrets designed by Krupp for Porsche’s VK4502(P) – commonly known as Porsche Turrets. Porsche’s turret mounted a one-piece 88mm gun, and carried 80 rounds of ammunition. The Porsche turret had a curved mantlet and the commander’s cupola was offset to the left. The curved mantlet created a shot trap below the mantlet and, in December 1943, Henschel was ordered to design a new turret to be used as a standard for future models. History courtesy of: www.achtungpanzer.com/panzerkampfwagen-vi-tiger-ii-ausf-b-konigstiger-kingroyaltiger-tiger-ii-sd-kfz-182.htm