If you were specifically speaking about the ancient Persians than why did you say they be rollin beemers? Sounds to me that you were speaking about modern Persians as well.
As for what/who destroyed The Library Of Alexandria, it is up for debate.
According to wikipedia, Ancient and modern sources identify four possible occasions for the destruction of the Library:
1. Caesar's conquest 48 BC
2. the attack of Aurelian in the 3rd century AD
3. the decree of Theophilus in 391 AD, and
4. the Muslim conquest in 642 AD or thereafter.
SOURCE
No mention of any Persian culprits.