The closest known event to a single publication date, that is, when the manuscript was probably released to the public for borrowing and copying, and was probably sent to the Flavians, is the date of the Dedication in the first of the 37 books. It is to the "imperator" Titus. As Titus and Vespasian had the same name, Titus Flavius Vespasianus, earlier writers hypothesized a dedication to Vespasian. Pliny's mention of a brother (Domitian) and joint offices with a father, calling that father "great", points certainly to Titus.