I've heard that deponent verb "miror" also had a non-deponent form. As far as I know it was in medieval Latin. So is it true? When exactly was the verb "mirare" used? Was it used everywhere, or was it a regionalism? And how did the meaning differ from the deponent form?
The Lewis & Short entry for miro indicates that it is an “ante-classical form of miror”. Combining the examples in this entry with those found in An Etymological Analysis of Latin Verbs, I have found the following authors who use the active form instead of the deponent:
Varro (d. 27 BC)
Hospes, quid miras nummo curare Serapim?
Aut ambos mira aut noli mirare de eodem
Pomponius (d. AD 138)
Si studium mirabis diu...
The entry in Wiktionary, however, informs us that it is “especially used in late or vulgar Latin”.
I have been unable to locate examples of this usage in medieval Latin, however.