In Western literature and fairy tales there is a frequent trope of the "faithful servant."
In many cases, there is little reason for the servant to be so faithful-- at least from a modern perspective, the hero does little to EARN the loyalty of his servant.
The miller's son in Puss in Boots is just an everyman, Phileus Fogg in Around The World in 80 Days is a self-aggrandizing jerk, and perhaps most puzzling is when the hero saves the life of a bandit or thief and earns his undying devotion (The Count of Monte Cristo). In The Lord of the Rings, Samwise is not even paid to accompany Frodo; he was his gardener, not his valet, and they are not exactly friends because of the weird class divide. This is leaving aside any racial/colonialist dynamics as in Robinson Crusoe (Man Friday), but just with people of the same country/culture.
Where does this pedestalization of the servant come from? Is it a Christian thing?
In many cases, the servant is a perfect, virtuous and exceedingly capable Mary Sue, and while it's quite useful to have an Everyman around when you're constructing a story, the trope of the Faithful Servant seems to have a moralistic tone.
I'm just hoping /r/AskHistorians can tell me what the general thought is about such an established, but undiscussed aspect of the hero's journey in the western canon.
This is more literary than historical, as u/OurSociety pointed out.
However, I can try to answer.
In literary art, and even in many films, the major character has to go through a character arc. Most of the time, they began their journey as a weak, timid or feeble person, believing themselves not up to the task that is laid out to them, such as destroying the Ring as Frodo, or destroying the Death Star as Luke Skywalker.
The "faithful servant" trope is there to build on these characters. Frodo would have never leaved the Shire without Gandalf and not destroyed the Ring without Sam. The point of the "FS" is to point out our own weaknesses, and that of the characters, through the story. It is boring to read;
"Frodo was stabbed by an orc, but he survived and killed him. He then fell down a cliff, but found a vine and climbed back up. Frodo was then taken by the Ring's power, but then he threw it into Mount Doom."
Nothing new about the character is learned, he is not developed and their is no tension. It loses it's potential as a "page turner".
However, if those situations had a character to come save Frodo, tension is added, because there is a real sense of danger for the character who cannot solve the situation themselves, and we learn their limits and developments in character, such as finally realizing that he needs Sam to complete his journey.
This makes the climax more entertaining, we felt for the hero and his tribulations, we enjoyed his relationship with his friends, etc.
This whole trope is simply a literary technique that easily conveys certain ideas the author wants the audience to know.
Hi, you might consider x-posting this to /r/AskLiteraryStudies
The origin of this "faithful servant" or sidekick probably comes from Don Quixote, where Sancho is used as a "voice of truth", that is, remarks how "crazy" Don Quixote is (something along the lines of "Those are giants Sancho", "No sir, those are only windmills"), and a source of dialogue to whom the hero -antihero in this case- expresses his ideas and feelings, liberating the author from including boring discussions of the hero in his own mind.
It already has some of the features you identified: loyalty, different social class. A small difference is that Sancho is also included (as many things in this book) with a comical intention (he is not exactly the smartest man on Earth, but at least is not crazy), and as a way of mocking the ancient squires.
In the case of Frodo and Sam, Tolkien based this relationship on his experiences in World War I. A British officer would have a batman (yes really) who essentially acts as a personal servant and companion to the officer. Tolkien confirmed this in private letters, and he held these batmen in great esteem. Sam may not have been paid to accompany Frodo, but his devotion was based on a deep mutual respect that was more than a faithful servant/master dichotomy. I'd recommend reading Humphrey Carpenter's excellent Tolkien biography for more about this.
Would you include Mark Twain's Jim in with Robinson Crusoe?