Doubt about Sentence

[GuilhermeRM]

I -The ancient Spartans tested the endurance of potential warriors devising various ordels, including one that '' ''
II-The ancient Spartans tested the endurance of potential warriors by devising various ordels, including one that ''''
Is it truly necessary to use the preposition ''by'' before the noun ''warrior''?

[5jj]

No, but if you don't use 'by', you must have a comma between 'warriors' and 'devising' in the first sentence..

It is essential to spell 'ordeals' correctly.

It is also important to give your title a thread that gives us an idea of what to expect. 'Do we need 'by' before 'devising'' would have been better.