Question: I'm currently working on a novel, in which one of the POV characters is a slave. He was born to a slave (so he was born a slave) of a rich merchant family and was treated well most of his life. One day he travels with his master to a foreign country where slavery had been abolished. The interaction with the foreign "free" people makes him doubt his position.

Might be relevant that he is of a different race than his masters, and the population of the foreign country he travels to belongs to his race.

Initially I want him to not see the injustice in his state and to love his master (they have a close relationship since they grew up together), yet I (born into a *mostly* slave-free world) have no idea how to portray him. Almost anything I try to write about him feels contrived. 

How could I better identify with him? 

or 

Any reference to a novel (historical fiction preferred, could be any period in history) with a slave POV character (third-person preferred) will do.

Answer: 
Although not a slave in the sense you're describing, I would recommend reading Nelson Mandela's first volume of his auto biography, Long Walk To Freedom.

What is quite interesting in this book is that he starts off not really seeing the injustice of his situation, or that of his people, primarily because of where he is raised, how he is raised, the education he receives, and the benefits that he gets from his situation (for example, access to education that is done to make him and other black South Africans be more like a British concept of a 'gentleman'). While he was among a small minority that could get education, the general populace were left to live as they always had, and given the "freedom" to do so.

There is one particular moment I recall in the book where Mandela is undergoing his right of passage to becoming a man in Xhosa culture, and a local chief who was the guest speaker (I forget who, apologies) gives a speech about how the Xhosa people are not free, and Mandela gets angry thinking this man is being so ungrateful for what they have.

True, Mandela was not directly a slave, or owned by someone, but the same principles apply: you grow up in a world where you don't know any better, and you're often purposefully left uneducated so you don't ask awkward questions, but given enough to improve your lot that you are grateful.

Even during slavery in America, slaves often stayed with their masters not just because of the threat of violence or intimidation, but were content with their lot, often because many didn't know anything different, were uneducated, and only knew how to perform manual labour. They had somewhere to live, food, and some were given autonomy to practise various manual skills and even hire out their skills for a wage. Their friends and family were around them, and they lived in places that they considered their homes.

I know in South Africa, religion was often a powerful tool to keep people in line too, where it was adapted to show the inferiority of other races to the white man, and I suspect something similar occurred during slavery as well.

The prison of the mind is far more effective in controlling people than the stick, so if your character loves his master, it's likely because he's grateful for his position in relation to a situation where no-one knows any different. For example, his master may allow some leniency that others don't: perhaps teaching him carpentry, brick laying or other skills. Maybe his master welcomes him into his home regularly, gives him a good place to live while many others may not be so fortunate etc. Maybe his master saved his life once when he was being attacked by those who were racist or xenophobic, or even helped deliver his slave's son.

People are complex, and while things like slavery are often portrayed in binary terms, it's never so neat as we make out when we're dealing with real people.
I recently read a novel with this very theme: ["The Story of Jonas"](https://www.kirkusreviews.com/book-reviews/maurine-f-dahlberg/the-story-of-jonas/). However, while the book was quite well written, I personally found that aspect of it --the slave who doesn't initially question his servitude --to be implausible. A better example might be Ursula LeGuin's *[The Tombs of Atuan](https://en.wikipedia.org/wiki/The_Tombs_of_Atuan)* whose main character does not initially understand that she is oppressed because she has been led to believe she is favored.

My advice to you would be to emphasize the indoctrination process. People don't come into this world believing they are born to be servile, they learn to believe it because that's what people tell them. Show how everyone around him is constantly telling your protagonist how lucky he is, and how well-treated, and how he has advanced as high up as anyone from his race and background possibly could. 

Then, when he sees counter-examples to the propaganda, you can contrast those with what he has always been told. This also offers a narrative opportunity to drive a wedge between slave and beloved master, when they respond with opposite emotions and reactions to the discovery of a functional free society composed entirely of people from the protagonists' group.