Making a Foundational Myth

[Altair]

I found this article fascinating:

"The Silmarillion, The Hobbit, and The Lord of the Rings were conceived as the original stories behind an ancient but long lost English mythology"
https://www.thehistoryvault.co.uk/tolkiens-english-mythology/

I'd heard before how Tolkien's work was an attempt to recover a myth for England, but much of the historical underpinnings were new to me.

It's intriguing that stories of larger-than-life deeds and beings are needed to root a people and/or confer legitimacy. Can anyone think of any other examples?

[Sefiru]

It's intriguing that stories of larger-than-life deeds and beings are needed to root a people and/or confer legitimacy. Can anyone think of any other examples?

More of an in-universe example: in one of the Honor Harrington novels (Crown of Slaves, I think), a newly independent planet chooses monarchy over other forms of government, explicitly in order to create a national mythology (not sure if that's the right term).

[MadZealot]

Can anyone think of any other examples?

Not sure if this is exactly what you had in mind, but the idea of Tolkien setting out to create a quintessential British myth led me to think of our own 'Murrican quasi-folk heroes. John Henry. Pecos Bill. Paul Bunyan and Babe the Blue Ox.
And then there are the real folks who've inspired legends, like Casey Jones, Billy the Kid, and the cast of other characters who live in the sprawling mythic backdrop of the American West.

[nightsky]

Not sure if this is exactly what you had in mind, but the idea of Tolkien setting out to create a quintessential British myth led me to think of our own 'Murrican quasi-folk heroes. John Henry. Pecos Bill. Paul Bunyan and Babe the Blue Ox.
And then there are the real folks who've inspired legends, like Casey Jones, Billy the Kid, and the cast of other characters who live in the sprawling mythic backdrop of the American West.

 I think these are excellent examples.  Going back to Tolkien using larger than life characters he's no different than most other authors.  Myths and legends have to have that larger than life feeling to really get a foothold, and so do good stories.  After all, if Tolkien had chosen to follow the life of Fatty Bolger after he sounded the alarm, or the day to day trials and tribulations of Mr Butterbur of the Prancing Pony we would most likely not be having this conversation.
 These things are attractive BECAUSE they are larger than life.  After all would you rather hear about someone's mundane existence or follow the travels of a person on a quest with a noble cause at stake?   

Just my 2 cents for the day