reason for the decline of the druid orders. Archaeologist Miranda Aldhouse-Green (2010) asserted that Caesar offered both "our richest textual source" regarding the druids, and "one of the most reliable". She defended the accuracy of his accounts by highlighting that while he may have embellished some of his accounts to justify Roman imperial conquest, it was "inherently unlikely" that he constructed a fictional class system for Gaul and Britain, particularly considering that he was accompanied by a number of other Roman senators who would have also been sending reports on the conquest to Rome, and who would have challenged his inclusion of serious falsifications. Cicero, Diodorus Siculus, Strabo and Tacitus Other classical writers also commented on the druids and their practices. Caesar's contemporary, Cicero, noted that he had met a Gallic druid, Divitiacus, of the Aedui tribe. Divitiacus supposedly knew much about the natural world and performed divination through augury. Whether Diviaticus was genuinely a druid can however be disputed, for Caesar also knew this figure, and wrote about him, calling him by the more Gaulish-sounding (and thereby presumably the more authentic) Diviciacus, but never referred to him as a druid and indeed presented him as a political and military leader. Another classical writer to take up describing the druids not too long after was Diodorus Siculus, who published this description in his Bibliotheca historicae in 36 BCE. Alongside the druids, or as he called them, drouidas, whom he viewed as philosophers and theologians, he remarked how there were poets and singers in Celtic society whom he called bardous, or bards. Such an idea was expanded on by Strabo, writing in the 20s CE, who declared that amongst the Gauls, there were three types of honoured figures: the poets and singers known as bardoi, the diviners and specialists in the natural world known as o'vateis, and those who studied "moral philosophy", the druidai. Roman writer Tacitus, himself a senator and historian, described how when the Roman army, led by Suetonius Paulinus, attacked the island of Mona (Anglesey; Welsh: Ynys Môn), the legionaries were awestruck on landing, by the appearance of a band of druids, who, with hands uplifted to the sky, poured forth terrible imprecations on the heads of the invaders. He says these "terrified our soldiers who had never seen such a thing before". The courage of the Romans, however, soon overcame such fears, according to the Roman historian;