Naomi Novik's His Majesty's Dragon series of modern fiction book, set in the early 19th century, uses a somewhat archaic form of English to help communicate the setting. I must say that it works quite splendidly, and some of the odd (to a modern ear) usages of language are surprising in their elegance.
The word "famous", and its parallel "infamous", are used in a way that is not modern:
and at the last Battersea, unlike virtually all the others, was incautious in tearing the sheet, so that his piece was unusually large; he could be heard murmuring quietly to Carver, “Would it not be famous to ride a dragon?”
Here, the character is expressing excitement at the chance of being able to ride a dragon.
Japanese dragons are far more likely among the Oriental breeds to have any special offensive capabilities.”
“Oh,” said Temeraire glumly.
“Temeraire, do not be absurd, it is the most famous news anyone could imagine,” Laurence said
Here, one character is telling another to not be sad about the fact that they cannot breathe fire given all the other wonderful news they have just learned about themselves.
“Oh!” said Miss Montagu, overhearing; curiosity evidently overcame her objections to the company of an aviator. “I have never seen a dragon; pray may we come? How famous!”
Here, a character is expressing their excitement for the chance to see a dragon.
“So you are the naval fellow who snatched an Imperial out of the jaws of France. Lord, it is a famous story; the Frogs must be gnashing their teeth and tearing their hair over it,” Martin said exultantly.
This is a usage of the word "famous" that modern readers are quite familiar with.
“We think the Anglewing over there may hatch soon; that would be famous,” Martin went on, pointing at a golden-brown egg...
Replace "famous" with "awesome", and the sentence works as if said by a modern person.
“Sir, the others have asked me to propose to you that perhaps we might try some of the new maneuvers,” Granby said to him, some few weeks into the project. “We would be more than happy to sacrifice our evenings to the work; it would be infamous not to have a chance of showing what he can do.”
Here, one of the characters is pointing out how awful/sad it would be if another was not allowed a chance at their full potential.
“In any case, they grow tired of trying to persuade him; so that villain Barham ordered I should lie to him and say we were assigned to Gibraltar, all to get him aboard a transport and out to sea, too far for him to fly back to land, before he knew what they were about.”
“Oh, infamous.” Her hand tightened almost painfully on his arm.
Here, one character is remarking at how awful the other's news is.
Wiktionary is usually quite good at providing archaic usages of a word, but in this case, it remains silent, and provides only the definition of the word the modern world is most familiar with, without any alternatives: https://en.wiktionary.org/wiki/famous
According to an online Oxford dictionary, the usage of "famous" as "excellent" is "informal": https://en.oxforddictionaries.com/definition/famous
According to "yourdictionary.com" (whose reliability I am not certain of), an archaic usage of "famous" is actually in the sense of "notorious": http://www.yourdictionary.com/famous
Merriam-Webster does not annotate the second definition of "famous" as "excellent; first rate" with neither "informal" or "archaic": https://www.merriam-webster.com/dictionary/famous
What is the history of the usage of the word famous in this sense? Are there modern authors who still use the second definition?