That's a good question, but unfortunately those classes of people didn't leave behind much of their own writings so we can't be too sure. To paraphrase my OED: If they were family, they would have used the word describing their relationship like son or cousin. Pious epithets were also popular like "God-honoring" or "God-guarding" or maybe other adjectives with "pan-" or "hyper-" added to them for emphasis. Adding prefixes to titles was also how a lot of more official titles were initially coined. Or by some nickname like "John the Frank" if his father was a Frankish immigrant. They also used the ancient Greek "philos" for a general friend. Words like "kyrios" (lord) and "despotes" (despot/lord) would be used to address people higher up than them.