The 1929 Newbery Medal Award Winner, The Trumpeter of Krakow, by Eric P. Kelly, which (as you would expect from the title) is set in Kraków, is based upon a centuries-old Kraków tradition, and an accompanying legend. In Kraków, beginning at the stroke of each hour, a trumpeter plays a 5-note tune called the Hejnal (you can hear it here) out of each of the four windows of the tallest tower in St-Mary's Church tower. It's also traditional to end the Hejnal on a broken note. Kelly claims in the prologue to his novel that this tradition was created after a 1241 invasion of Kraków, during which the trumpeter faithfully stayed at his post to play the Hejnal but was shot through by an arrow before he could finish. It's a colourful story, but there isn't any real evidence that it's true. Kelly's version of this legend was the first to be written down. According to Wikipedia, there is an 1861 account of invading Tatars and a sentry who sounded the alarm, but this account does not mention the sentry's death. One trumpeter is known to have died while on duty and the broken note tradition may have originally been a tribute to him, but that was in 1901 and the trumpeter died of natural causes. It's unclear whether Kelly was misinformed (at the time of writing The Trumpeter of Krakow he did not yet speak Polish well), whether he combined or confused the two stories, or whether he was simply the first to record an actual legend.
All this aside, The Trumpeter of Krakow, set in 1461, is the story of a young trumpeter, Joseph Charnetski, who used the Hejnal to sound another alarm. It isn't a bad story. It has a decent plot, seems to be reasonably well-researched as to its period detail, and is a rather entertaining adventure story about a family sworn to protect the (fictional) Great Tarnov Crystal, and the villain and the alchemist who are determined to get their hands on it. It also has a certain frustrating woodenness to its characters and dialogue that keep it from being an excellent book. The characters are sketched in a few simplistic lines, especially in the case of the female characters. Joseph's father is honourable and brave, his mother is pious and gentle (and isn't even given a name of her own), and Joseph is a less-self-assured version of his father. Elzbietka, a young friend of Joseph, is kind and in need of a mother. Joseph's mother obliging steps up for this role and the two of them rush improbably into each others' arms the minute they meet. I will give Kelly some credit for having given Elzbietka a part to play in the story's action and for also having her question why, if learning Latin (as Joseph does) is such an excellent thing, it is not for women as well as men.
Kelly also used his characters' looks to define their personalities in a way that was common in fiction until mid-twentieth century or so -- one often reads about a "noble" or "refined" features in old novels. The Charnetskis are described as having honest or pleasant faces, and this is how Kelly describes Peter, the book's villain:
It was the face, however, that betrayed the soul beneath. It was a dark, oval, wicked face--the eyes were greenish and narrow and the eyebrow line above them ran straight across the bridge of the nose, giving the effect of a monkey rather than a man. One cheek was marked with a buttonlike scar, the scar of the button plague that is so common in the lands east of the Volga, or even the Dnieper, and marks the bearer as a Tartar or a Cossack or a Mongal. The ears were low set and ugly. The mouth looked like a slit that the boys make in the pumpkins they carry on the eve of the Allhallows. Above the mouth was a cropped mustache which hung down at the ends and straggled into a scanty beard.
Subtle, huh? Using one's character's appearance as barometer to their level of refinement or morality is a literary trope that may have had its origin in the pseudoscience of phrenology, and that, thankfully, has fallen out of fashion now. It's a nonsensical notion, and there's surely enough lookism in the world without our having to go to the extent of considering anyone's looks indicative of goodness or evilness.