who and whom. This example is confusing

[steven7dong]

Hello. I'm not asking the difference between when we should use who and whom. I think most of us know pretty well. But this example here doesn't seem to comply the rule we learned.

Example: Written in Austria in 1762, Symphony NO.5 was composed by a brilliant musician, Franz Joseph Haydn, whom many later called the "Father of Symphony" for his contribution to classical music while court musician for the Esterhazy family.

I know how is for subject and whom is for object. In this case, if we take the element that contains whom from the sentence out, it will be:

Franz Joseph Haydn was called the "Father of Symphony" for his contribution to classical music. Since is the whom here refers to Franz Joseph Haydn and Franz Joseph Haydn is the subject. Why can't we use "who"? The correct answers to the question above is one with whom. I'm confused.

I also heard that if after any prep words, we have to use whom.
Ex: The men, four of whom are ill, were indicted for fraud.
Is this true?

Could anyone explain this to me?

[RonPurewal]

* This is the wrong folder for this question. This question is for problems from the GMAT PREP software only.

* Who/whom has never been tested on the current version of the GMAT, so there's no reason to discuss these points on this forum.