Gregory's letters have the same kind of value as evidence for the mission to England as do the letters of Sidonius Apollinaris for conditions in fifth-century Gaul. They are not the letters of a man looking back with hindsight on distant events but of one currently playing a major part in an undertaking whose outcome could not be foreseen, giving instruction for what was to be done in the future, not recording what had happened in the past. When Bede came to write his account of the mission and of the conversion of the English as a whole, events which for Gregory still lay in the future had receded for a span of 130 years into the past. How did Bede learn about the mission? In trying to answer this question we need to remember how many questions remain unanswered even for the few years covered by Gregory's letters, lest over the long retrospect from the present the more distant years become foreshortened. The earliest reference to the conversion in Bede's writings is found in his treatise De Temporibus written in 703 when he was a little over thirty. The closing chapters of this work were devoted to the six ages of the world and its final section contained a brief chronicle of events which had occurred in the still-current sixth age and which were arranged chronologically not by the years of the Christian era, but by the emperors in whose reigns they had occurred.