Persian-influenced Romance language

I am in the early stages of work on a Romance language influenced by Persian,
and I am having trouble because I can't find many resources on the forms of
Persian which were current in the period when the Romance languages were
forming. Does anyone have any information on what forms of Persian existed at
the time, and on where I could find information on them? I would also
appreciate any general suggestions for the language.

Thanks,

-- Michael Greenlee