Well, yours is an exceptionally wide question :) but I'll try to provide an answer on my humble area of expertise, which is mainly early medieval law, and, well, Argentinean law. As this is a multifaceted question, I’d like to provide a legal view, where compensation and restitution – and the influence of Christianity – are the focus.

I'll be mostly using the Forum Iudicum for Visigothic valuation of life, deeply intertwined with Roman law, as a reliable source for early romano-germanic laws – and a good standpoint to compare to other codex-based laws in a contemporary background. I’ll throw in some Edict Rothari for a more Germanic view.

My main point here is that religion and culture place differing values on lives, personhood, etc. as a whole. I’m sure someone more concerned with Islamic jurisprudence will probably have a lot to add, and extremely different. In the Liber Iudicorum, promulgated in the 7th century, and applying equally to both Romans and conquering Visigoths, on Book VI (Concerning Torture and Homicide), Title V (Concerning Homicide), gives a wide variety of penalties for murder. Accidental killings, with no malice or previous animosity, are, for instance, not penalized (Articles I and II).

As intention and malice increase - see article IV, where killings done in the pursuit of harming another (as in, striking someone unintentionally during a brawl, and killing them) are fined with 500 solidi for the one that stirred the brawl, and 50 solidi for the one that actually struck the blow. A solidi is, grosso modo, four grams of gold, about 160 dollars in the U.S - so for giving the opportunity to kill a man, accidentally, you'd be fined about 80000 U.S dollars. For actually doing the killing, you'd be fined 8000 U.S dollars.

The penalty to one who kills in sport, or 'with recklessness', of half a pound of gold and fifty lashes, for failing to take appropriate precautions to avoid the killing.

Of course, all of this accidental killings are of persons in the judicial sense - not of slaves. Personhood as a whole is an arid subject, and I can tell you a bit more if you'd like, but the main gist here is that slaves have no legal personhood. For instance, accidentally killing a slave entitles their master to half the compensation for killing a freeman. They are recognized as humans, but not as people, and yet, Christian influence does provide several provisions for (some sort of) legal protection.

Just as we know from the Codex Theodisiani that Constantine submitted laws that forbade branding the faces of criminals condemned to the mines or the arena, as they were made in the image of God, legal protections for slaves existed in the Liber Iudicum, that prescribed harsh sentences for the unprovoked killing of a slave - namely, exile, forfeiture of property to heirs, loss of civil rights, et cetera. This is seen as a mercy, not a right – something that the King gives at his pleasure, in a spirit of Christian charity. You’ll see a lot of that as German law is tempered by Canon law – Christianity establishing ‘merciful’ provisions for those beneath the law. Contrast with any codified law – I’ll go with the Argentinean penal code – and you’ll find many distinctions. First, and well known, is that imprisonment is probably the cornerstone of criminal law as of now – rehabilitation of the prisoner, and safeguarding of the judicial value, for instance, life or social peace. Civil restitution goes in parallel, and is not a part of the penal process. There is no debtor’s prison, no selling the person into slavery, etc. This goes to show that personal restitution is less important than social safeguarding, which in general was the way Germanic law went as it Romanized.

Contrast, too, with a properly Germanic codex. After the Lombard invasion of Italy, the Edict Rothari was promulgated in the 7th century, and it only applied to Lombards, while the majority Roman population of Italy was still subjected to Roman law. As befits a Germanic code, it’s minutely concerned with weregild, restitution, and severely devaluated non-Lombard serfs, especially agricultural serfs. Lombards placed an inordinate value on free women - restitution for injury on a free woman or girl starts at 900 solidi. The same restitution for a man was 20 solidi. I have not found any reference to punishment on the unwarranted killing of slaves, for instance, as befits a people whose Christianization and Romanization was slower than, for instance, that of the Visigoths.

While I know this doesn’t answer your question in full, I hope I was able to shed some light on how contemporary cultures can differ a lot, and how modernity changes, if not what is protected, changes how we protect it, and what the main focus of law can be – restitution, punishment, rehabilitation, etc.

Obligatory caveat: First time answering in AskHistorians with research of my own. I hope this is acceptable, and obviously, I hope that if I’m making mistakes of any sort, they’ll be pointed to me! Thanks!

EDIT: Format