was in 79. This brings the date of the Dedication probably to 77. In that year, Vespasian was 68. He had been ruling conjointly with Titus for some years. The title imperator does not indicate that Titus was sole emperor, but was awarded for a military victory, in this case that in Jerusalem in 70. Aside from minor finishing touches, the work in 37 books was completed in AD 77. That it was written entirely in 77 or that Pliny was finished with it then cannot be proved. Moreover, the dedication could have been written before publication, and it could have been published either privately or publicly earlier without the dedication. The only certain fact is that Pliny died in AD 79. Natural History is one of the largest single works to have survived from the Roman Empire and was intended to cover the entire field of ancient knowledge, based on the best authorities available to Pliny. He claims to be the only Roman ever to have undertaken such a work. It encompasses the fields of botany, zoology, astronomy, geology, and mineralogy, as well as the exploitation of those resources. It remains a standard work for the Roman period and the advances in technology and understanding of natural phenomena at the time. His discussions of some technical advances are the only sources for those inventions, such as hushing in mining technology or the use of water mills for crushing or grinding grain. Much of what he wrote about has been confirmed by archaeology. It is virtually the only work that describes the work of artists of the time, and is a reference work for the history of art. As such, Pliny's approach to describing the work of artists informed Lorenzo Ghiberti in writing his commentaries in the 15th century, and Giorgio Vasari, who wrote the celebrated Lives of the Most Excellent Painters, Sculptors, and Architects in 1550. Natural History as the First Encyclopedia Some historians consider Natural History to be the first encyclopedia ever written. It was the earliest encyclopedia to survive. There were many ancient histories written before Pliny the Elder's Natural History, but scholars still recognize Natural History as an encyclopedia, setting it apart from the other ancient histories. Regardless of if it was first, it is certainly the most significant. Through Natural History, Pliny the Elder gives modern experts a view into meanings of various things from