He is the author of the Gesta Danorum, the first full history of Denmark, from which the legend of Amleth would come to inspire the story of Hamlet by Shakespeare.
Both arguments, for a secular or religious Saxo, would confirm that he was well educated; as clergy, he would have received training in Latin and sons of great men were often sent to Paris.
He tells us that he follows "the ancient right of hereditary service", and that his father and grandfather "were recognized frequenters of your renowned sire's (Valdemar I) war camp".
In his will Absalon forgives his clerk Saxo a small debt of two and a half marks of silver and tells him to return two borrowed books to the monastery of Sorø.
He drew on oral tales of the Icelanders, ancient volumes, letters carved on rocks and stone, and the statements of his patron Absalon concerning the history of which the Archbishop had been a part.
[11] Westergaard writes that Saxo combines the history and mythology of the heroic age of Denmark, and reworks it into his own story that exemplifies the past of the Danes.
[12] The history is composed of sixteen books, and extends from the time of the founders of the Danish people, Dan I of Denmark and Angul, into about the year 1187.
They are sometimes treacherous, such as in the story of Harald, legendary king of the Danes, who was taught the ways of warfare by Odin and then was betrayed and killed by the god, who then brought him to Valhalla.
Christiern Pedersen, a Canon of Lund, collaborated with Jodocus Badius Ascensius, a fellow enthusiast, to print the work of Saxo Grammaticus early in the sixteenth century.
[20] Oliver Elton, who was the first to translate the first nine books of Gesta Danorum into English, wrote that Saxo was the first writer produced by Denmark.
They are Chronicon Roskildense (English: Roskilde Chronicle), a small work written in Latin, completed in c. 1143, spanning from the introduction of Christianity in Denmark to the author's own time.
[24] The next to be published was Brevis historia regum Dacie, written by Sven Aggesen (b. c. 1140–1150 – death unknown), thought to have been finished in 1186 or 1187 (the last event described happened in 1185), covering the years 300–1185.
[29] Kurt Johannesson's studies[30] expanded greatly on the comprehension of Gesta Danorum, deviating from the approach that focuses mostly on mythology, and allowing the development of a wider understanding of Saxo's works.
Some of them have concluded that Saxo, instead of simply distorting allegedly true Nordic and Baltic traditions and/or beliefs, was creating something new, attuned to the approaching 13th century Danish race to strengthen institutions and engage in the Northern Crusades.