The Prince and the Pauper by Mark Twain

A nice story for kids, but I had never read it before. It starts introducing the two boys: Edward the young Prince and Tom the poor, unfortunate boy who shares a room with his mother, father, grandmother, plus a brother and two sisters. Tom's father has no intention of finding a job, he prefers to send his boys out to steal or beg for money, and if they come back without it he beats them. Tom likes to play with other children and to swim in the river, but he also dreams of being a Prince, so he goes every day to the gates of Edward's Palace hoping to see him. Edward notices this and one day he comes to his aid when the guards are beating him to send him away. Edward wants to speak with him and after hearing his story he thinks he'd like very much to play and swim, free for once, so he proposes to exchange clothes and roles. They are very much alike and nobody can see the Prince under the beggar's clothes or the pauper under the rich ones Edward has given him.
Edward has no chance to play or swim though, because he is soon treated like a poor beggar. He is found by Tom's father (John Canty) and taken home. Canty hits an old man who dies, so now he wants to run away to escape justice, and he wants to take his family with him, but Edward escapes as soon as he can. Luckily for him there's a man, just back after seven years of war, willing to help him, although he believes him mad like everyone else for saying he's the Prince.
Together they try to send a message to Tom. Everyone is about to send them away but Tom hears about it and orders them in, so they manage to explain the truth and regain their true role. As a king, Edward will help the soldier to get back the land and the woman his brother had stolen from him, and Tom will be his best friend and able to provide for his mother and sisters. It's very short and written so simply it is an easy read for boys and girls, but at the same time it's tougher than I thought. It has a happy ending of course, but also it has people beating kids, a crowd mob, a king dead of illness and a good old man dead, it has a man betraying his brother and also Edward  who died very young.
Mary followed him as Queen, and then there was Elizabeth I.