In the English Grammar Profile, C2 point 117 in the category of PRONOUNS/quantity is defined as:
complex noun phrases using an inverted form ‘Many’ + ‘are’ + noun phrase, followed by a relative clause, as a focusing device.
*We can’t find much meaningful data in corpora for this rare grammar structure because of the length of allowed searches.
The most we can find in the iWeb corpus is:
1 . MANY ARE THE TIMES 23
2 . MANY ARE THE AFFLICTIONS 12
3 . MANY ARE THE RESULT 11
Here are two examples from COCA:
- Many are the times that I have sat in abject pain with a purple face just to see our boys through.
- Many are the reasons which may induce believers to seek it…
*This is a type of literary inversion of the normal order of the elements of a sentence. Usually, we would write:
I have sat in pain many times.
There are many times that I sat in pain.
*It is possible to follow this structure with a time clause too. For example: