I haven't read Greg King's book on Ludwig, but it probably covers the point I'm about to make.
Ludwig II is today revered in Bavaria, mostly because his building sprees established one of the cornerstones of the lucrative Bavarian tourist industry.
However, during his lifeteme his mental instability had some rather different consequences. Bavaria was the biggest impediment to Prussian aspirations to unite Germany under the Hohenzollerns. Bismarck dealt with the "Bavarian problem" buy secretly funding Ludwig's mad architectural fantasies, thereby distracting him from political meddling and creating a dependency on Prussian money to bring his building projects to conclusion (although even Prussian money was not enough to bring Hohenchiemsee over the finish line).
Ludwig II wasn't just the colorful distraction he seems today. He was of real, though unwitting, consequence in subsequent European affairs.
Ludwig II of Bavaria (1845-1886), King of Bavaria (1864-1886)
He was the son of King Maximilian II Joseph and heir to the throne, born on August 25 1845 in Nymphenburg (Munich today). In 1866 Ludwig fought on the Austrian side in the German War against Prussia. One year later he approved an alliance with Prussia. In 1870, upon Bismarck's initiative, he wrote a letter of intent to all German Princes, the so-called "Kaiserbrief" of November 30 1870, that became the basis for the proclamation for the acceptance of King Wilhelm I as Emperor of Germany. In return Bismarck assured Ludwig the financial assistance he so urgently needed, in order to continue with the building of his castles. During the Franco-German War of 1870/71 Ludwig fought on the side of the Germans. Ludwig was a passionate builder and promoter of Richard Wagner, to whom he gifted the Bayreuth Festival Theater. Among others, he built the castles Neuschwanstein, Linderhof and Herrenchiemsee. From 1875 on Ludwig lived completely withdrawn in his various castles and did not appear in public any longer.
On June 9 1886 Ludwig II was declared incompetent based on a medical opinion, after he showed signs of mental illness and because he had ruined the Bavarian State finances with his building fanaticism. On June 10 his uncle, Prince Luitpold, took over the regency. In the evening of June 13 Ludwig drowned in Lake Starnberg near Castle Berg, along with his psychiatrist, Dr. Bernhard von Gudden. To this day the circumstances of their death have not been conclusively determined.
