What historical events occur in the novel?

Anna Sewell wrote the novel Black Beauty in 1877. The novel is set in Victorian England and is told from the horse's point of view. It was originally subtitled "An Autobiography of a Horse." It chronicles the life of Black Beauty, his experiences, masters, and fellow horses.
Since it is written from the horse's point of view, there aren't many historical references. There is a chapter entitled "The Election," which is chapter 42. It is vague in its details, referencing the man who didn't want political propaganda on his cab and the girl who gets called a "blue ragamuffin." The colors of each party are explained, but no names or dates are given.

"My boy, I hope you will always defend your sister, and give anybody who insults her a good thrashing—that is as it should be; but mind, I won't have any election blackguarding on my premises. There are as many 'blue' blackguards as there are 'orange,' and as many white as there are purple, or any other color, and I won't have any of my family mixed up with it. Even women and children are ready to quarrel for the sake of a color, and not one in ten of them knows what it is about."
"Why, father, I thought blue was for Liberty."
"My boy, Liberty does not come from colors, they only show party, and all the liberty you can get out of them is, liberty to get drunk at other people's expense, liberty to ride to the poll in a dirty old cab, liberty to abuse any one that does not wear your color, and to shout yourself hoarse at what you only half-understand—that's your liberty!"

The other historical reference is to the Crimean War. The Crimean war was a conflict that occurred between 1853 and 1856 and involved Britain, France, and some Turks fighting against Russia. The war is mentioned in Sewell's novel because one of the horses Black Beauty meets fought in that war. This is mentioned in chapter 34, which is entitled "An Old War Horse."

Captain had been broken in and trained for an army horse; his first owner was an officer of cavalry going out to the Crimean war. He said he quite enjoyed the training with all the other horses, trotting together, turning together, to the right hand or the left, halting at the word of command, or dashing forward at full speed at the sound of the trumpet or signal of the officer.