The general date of the Aqueduct's construction was long a mystery, although it was thought to have been during the 1st century AD, during the reigns of the Emperors
Domitian,
Nerva, and
Trajan. At the end of the 20th century,
Géza Alföldy deciphered the text on the dedication plaque by studying the anchors that held the now missing bronze letters in place. He determined that Emperor
Domitian (AD 81-96) ordered its construction and
the year 98 A.D. was proposed as the most likely date of completion. However, in 2016 evidence was published which points out to a slightly later date, by 112 AD.