The Treaty of Versailles, which established the terms concluding World War I, restricted German naval shipbuilding to warships displacing no more than 10,000 long tons (11,000 short tons).
Debates in Germany over the role and size of its navy continued through the 1920s, when increased naval shipbuilding in France and the Soviet Union prompted the Germans to begin drawing up designs for large capital ships.
The first design, completed in 1928, called for a 17,500 long tons (19,600 short tons) battlecruiser armed with eight 30.5 cm (12 in) guns in four twin gun turrets, based on the design for the Ersatz Yorck-class battlecruisers that had not been completed during the war.
In 1933, Adolf Hitler came to power in Germany; he made clear to the naval command that he had no intention of building a large fleet to challenge British supremacy at sea.
He was primarily concerned with the possibility of a limited war with France, which would require the protection of German sea lanes.
To this end, he authorized two more ships—the D class—to augment the three Deutschland-class Panzerschiffe (armored ships).
These ships would displace 19,000 tons and have the same armament and speed as the Panzerschiffe; the extra tonnage would be taken up by increased protection.
Hitler wanted to follow this course so he would not be seen as overtly flouting the Treaty of Versailles.
He did not realize that such "unsinkable" commerce raiders would provoke Great Britain more severely than 26,000-ton battlecruisers armed with 28.3 cm (11.1 inch) guns, which would be regarded as inferior to all the Royal Navy battleships and battlecruisers then in commission.

To combat the German Panzerschiffe, the French built two small Dunkerque-class battleships in the early 1930s.
This in turn prompted the German navy to begin plans for a more powerful battlecruiser design.
Since 1933, Erich Raeder, the head of the German Navy, had argued to increase the defensive qualities of the Panzerschiffe, and to increase the offensive power of the main battery with the addition of a third triple turret.
This was also the view of the Kriegsmarine, which saw the 19,000-ton design as being unbalanced.
Hitler agreed to increased armor protection and internal subdivision, but refused to permit an increase in armament.
Finally, by February 1934, Hitler acquiesced over the addition of the third turret.
The new ship would displace 26,000 long tons (29,000 short tons) and be armed with nine 28.3 cm guns in three triple turrets.
To secure political freedom to build the new ships, Hitler concluded the 1935 Anglo-German Naval Agreement, which guaranteed Great Britain a 3 to 1 superiority in capital ships, and, more importantly, removed the limitations of the Treaty of Versailles for the German navy.

The construction of new D-class cruisers were canceled to make way for Scharnhorst and Gneisenau.
The provisional names of the planned D-class cruisers, Ersatz Elsass and Ersatz Hessen, were reallocated to the new ships, the contracts for which were awarded to the Kriegsmarinewerft Wilhelmshaven and the Deutsche Werke in Kiel.
Construction was held up by 14 months, partly because Hitler wanted to secure the treaty with Britain before work began, and partly due to numerous design changes after the ships had been ordered.

Because the maximum caliber of naval gun allowed under the Anglo-German Naval Agreement was 40.6 cm (16 inch), Hitler soon had second thoughts about the guns to be used for the new ships and ordered that they be armed with 38 cm (15 inch) weapons.
The 28.3 cm turrets were readily available; 38 cm turrets would take years to develop, and Hitler wanted capital ships as soon as possible to fulfill his political ideals.
He was also reminded that, despite the allowances of the Anglo-German Naval Agreement, the British had historically been sensitive about increases in main gun calibers aboard German capital ships.
He therefore acquiesced to the ships' being armed with 28.3 cm guns, with the provision that they be upgunned to 38 cm at the earliest opportunity.
The 38 cm turret was
The Treaty of Versailles, which established the terms concluding World War I, restricted German naval shipbuilding to warships displacing no more than 10,000 long tons (11,000 short tons). Debates in Germany over the role and size of its navy continued through the 1920s, when increased naval shipbuilding in France and the Soviet Union prompted the Germans to begin drawing up designs for large capital ships. The first design, completed in 1928, called for a 17,500 long tons (19,600 short tons) battlecruiser armed with eight 30.5 cm (12 in) guns in four twin gun turrets, based on the design for the Ersatz Yorck-class battlecruisers that had not been completed during the war. In 1933, Adolf Hitler came to power in Germany; he made clear to the naval command that he had no intention of building a large fleet to challenge British supremacy at sea. He was primarily concerned with the possibility of a limited war with France, which would require the protection of German sea lanes. To this end, he authorized two more ships—the D class—to augment the three Deutschland-class Panzerschiffe (armored ships). These ships would displace 19,000 tons and have the same armament and speed as the Panzerschiffe; the extra tonnage would be taken up by increased protection. Hitler wanted to follow this course so he would not be seen as overtly flouting the Treaty of Versailles. He did not realize that such "unsinkable" commerce raiders would provoke Great Britain more severely than 26,000-ton battlecruisers armed with 28.3 cm (11.1 inch) guns, which would be regarded as inferior to all the Royal Navy battleships and battlecruisers then in commission.
To combat the German Panzerschiffe, the French built two small Dunkerque-class battleships in the early 1930s. This in turn prompted the German navy to begin plans for a more powerful battlecruiser design. Since 1933, Erich Raeder, the head of the German Navy, had argued to increase the defensive qualities of the Panzerschiffe, and to increase the offensive power of the main battery with the addition of a third triple turret. This was also the view of the Kriegsmarine, which saw the 19,000-ton design as being unbalanced. Hitler agreed to increased armor protection and internal subdivision, but refused to permit an increase in armament. Finally, by February 1934, Hitler acquiesced over the addition of the third turret. The new ship would displace 26,000 long tons (29,000 short tons) and be armed with nine 28.3 cm guns in three triple turrets. To secure political freedom to build the new ships, Hitler concluded the 1935 Anglo-German Naval Agreement, which guaranteed Great Britain a 3 to 1 superiority in capital ships, and, more importantly, removed the limitations of the Treaty of Versailles for the German navy.
The construction of new D-class cruisers were canceled to make way for Scharnhorst and Gneisenau. The provisional names of the planned D-class cruisers, Ersatz Elsass and Ersatz Hessen, were reallocated to the new ships, the contracts for which were awarded to the Kriegsmarinewerft Wilhelmshaven and the Deutsche Werke in Kiel. Construction was held up by 14 months, partly because Hitler wanted to secure the treaty with Britain before work began, and partly due to numerous design changes after the ships had been ordered.
Because the maximum caliber of naval gun allowed under the Anglo-German Naval Agreement was 40.6 cm (16 inch), Hitler soon had second thoughts about the guns to be used for the new ships and ordered that they be armed with 38 cm (15 inch) weapons. The 28.3 cm turrets were readily available; 38 cm turrets would take years to develop, and Hitler wanted capital ships as soon as possible to fulfill his political ideals. He was also reminded that, despite the allowances of the Anglo-German Naval Agreement, the British had historically been sensitive about increases in main gun calibers aboard German capital ships. He therefore acquiesced to the ships' being armed with 28.3 cm guns, with the provision that they be upgunned to 38 cm at the earliest opportunity. The 38 cm turret was 
Scharnhorst-class battleship