Ritter Rost (The Rusty King) is a german musical play for children by Jörg Hilbert and Felix Janosa. It tells the story about Ritter Rost, who is a mechanical, iron knight, living at his castle made of steel with his trusty maiden Bö and Koks, a little dragon. The 5 books released under the title of Ritter Rost cover several stories of these heros, such as a circus visiting the forest, which is accidentally burned down by Koks, a ghost appaering at the castle, a nasty witch and a trip to the seaside. The stories are told through songs, being both clever but simple to singalong, as well as very comical. Often this songs make fun of the "brave knight" Ritter Rost claims to be (but in case of danger hides under his bed) and the courage of Bö, who looks like a weak girl the first side, but turns out to be "3 times as strong" as the knight, as well as many other situations in which one of the many mechanical inhabitants of the kingdom are described. The lyrics, mostly german, consist of many words referring to metallic objects, gadgets of any kind and pseudo-medieval themes.