historia

Historia, historiae is a first declension feminine loan straight from Greek historia, "enquiry", and it declines like any other -a noun. The h is Greek and was probably not pronounced by ordinary speakers, which is why medieval manuscripts write istoria as often as not.

The sense is wider than English "history". A historia is any narrative or account, true or otherwise, so a saint's life, a fable and a natural history all take the word; Pliny's Naturalis Historia is an enquiry into nature, not a chronicle of it. Where a Roman wants the record of past events specifically he is as likely to say res gestae or annales. The Cicero tag above, historia magistra vitae, is the standard defence of the subject and predates every modern version of it.