Historical-Mythological-Legendary writings

After the Lost Road Christopher Tolkien discussed a few scattered notes that may or may not have been where his father sought to take the story next (one that sticks out to me is his father's note to save the Númenor chapters until the end). And it seems there was a thought to connect the Lost Road to The Lost Tales via Aelfwine.

In any case Christopher Tolkien's commentaries walk us through various historical, mythological, and legendary histories that inspired his father: in general and for Lost Road in particular. One figure was King Sheave who was later used in another abandoned story The Notion Club Papers and appeared to be slated to connect to the Lost Road. A poem about King Sheave by Tolkien is given along with the roots of this mysterious character:

• Of Northern Germanic legend
• 3 primary sources: two historians (circa 1000 AD and 1143 AD) and the poem Beowulf
• All sources are similar: a young boy arrives to an island by boat (accompanied by some corn; hence the name Sheaf), he is taken in by the people, later he becomes a ruler or king among/of the people

And much commentary follows. 

Next a series of poems is given (The Nameless Land, The Song of Aelfwine I and II). The poem ends up being a tribute to the star of Eärendil as can be seen in the last stanza:

O Shore beyond the Shadowy Sea!

O Land where still the Edhil are!

O Haven where my heart would be!

The waves still beat upon thy bar,

The white birds wheel; there flowers the Tree!

Again I glimpse them long afar

When rising West I see

Beyond the world the wayward Star, 

Than beacons bright in Gondobar

More fair and keen, more clear and high.

O Star that shadows may not mar, 

Nor ever darkness doom to die.

Indeed, it's fun to see how many of Tolkien's other writings wound there way back to Middle-earth. His personal historical-mythological legend.