Formerly interested in ancient landscapes and techniques, he is currently involved in a long-term research about ancient Armenia.
He was awarded the Premio Nazionale 'Cherasco Storia' (2011) for his book La resa di Roma.
He was Dumanian Visiting Professor at the University of Chicago (Spring term 2017).
He is presently visiting professor at the Westfälische Wilhelms-Universität Münster.
In the Anglophone world he is most noted for his book 428 AD : An Ordinary Year at the End of the Roman Empire (Princeton, 2009), in which he which gives a panoramic view across the geographical extents of the Roman Empire in a single year.