So that we can understand. . .and licked king's blood:
Note from the Letter Charitas by John Ruskin

The allusion is to the story of Naboth's vineyard in 1 Kings xxi. Ahab, King of Samaria, covets the vineyard of a man named Naboth who lives near his palace. When Naboth refuses to give it him, the King's wife Jezebel arranges for him to be falsely accused of blasphemy. He is condemned to death by stoning and Ahab takes possession of the vineyard. Then God sends the prophet Elijah to denounce Ahab and Jezebel with the words:

'Thus saith the Lord, Hast thou killed, and also taken possession?... In the place where dogs licked the blood of Naboth shall dogs lick thy blood, even thine' (xxi. 19).

In 1 Kings xxii, Ahab is killed and dogs lick his blood. In 2 Kings ix, Jezebel is thrown from a window and dogs eat her flesh.

Ruskin goes on to compare this story with the Franco-Prussian War, fought over the vine-growing provinces of Alsace and Lorraine. The last sentence of this paragraph alludes to a famous passage from Shakespeare (Macbeth, II.ii.61-4) that Ruskin frequently quotes.