Also known as a royal plural

It's early Modern English not Old. Old English is the language of Beowulf.

Hwæt. We Gardena in geardagum, þeodcyninga, þrym gefrunon, hu ða æþelingas ellen fremedon.

Ultima games incorporate archaic language constructs in their dialogues and texts, but they are fictionalized rather than historically informed. I call it "langfic" (as in "fanfic"). The French edition of U7 is also notorious for featuring old vocabulary, but does so mixing up constructs from different eras and reforms. While the effort on the English edition is much more convincing, I wouldn't bank on it as a reference of its use; instead, I would turn to more scholarly sources that examine Early Modern English in depth.

>Possibly a later myth

It is apparently in one of his letters - to Hooke.

Here's a quote that predates Newton by some centuries:

"We are like dwarfs on the shoulders of giants, so that we can see more than they, and things at a greater distance, not by virtue of any sharpness of sight on our part, or any physical distinction, but because we are carried high and raised up by their giant size." -- John of Salisbury, The Metalogicon (1159)

https://www.oxfordreference.com/display/10.1093/acref/978019...

Newton also used (abused) his position as head of the Royal Society to wage a long and bitter feud with Leibnitz over who invented calculus.

Newton was undoubtedly:

a) One of the greatest geniuses who ever lived.

b) A total shit.

He was fascinating. For those interested in reading further I thought this book on him was excellent: https://www.amazon.com/Man-Who-Knew-Too-Much/dp/0333782860