chapter 19 Codex Reseniani: Sturla Þórðarson as an Encyclopaedic Writer Sverrir Jakobsson We seldom get the chance to look into the process of writing medieval history. Usually, the traces of medieval historians have been lost, with the exception of single works, finished and polished in their final versions or even added to by later copyists. In this regard, Sturla Þórðarson may be an important excep- tion. It has been argued that Membrana Reseniana no. 6, a manuscript that burned in the great fire of Copenhagen 1728, was an encyclopaedic work origi- nally belonging to Sturla Þórðarson, and at least partly written by him. Copies of several individual parts of this compilation have survived, and from these fragments we are able to gain a partial insight into the learning and interests of Sturla in the very years he was composing the historical narratives for which he is best known. In the following article the relationship between the contents of this vol- ume, henceforth known as the Encyclopaedia of Sturla Þórðarson (Alfræði Sturlu Þórðarsonar), and the other works of Sturla will be explored in order to illuminate the scholarly process by which Sturla Þórðarson conducted his research and composed the books attributed to him. The varied contents of the Encyclopaedia and the lengthy period over which it was written (from the late 1240s to the death of Sturla in 1284) make it a work of unique importance for such an analysis. Through this text, we can glimpse a historian practicing his craft through the pursuit of his variagated delvings into the past, not all of which made it into his more coherent narrative works. Membrana Reseniana No. 6 In the 1680s the Danish scholar Peder Hansen Resen (1625–1688) donated an Old Norse manuscript to the University Library in Copenhagen. In a catalogue made of Resen’s donation the contents of the manuscripts are listed in the fol- lowing manner: Codex Islandicus membraneus M. SS. Continens. © koninklijke brill nv, leiden, ���7 | doi �0.��63/978900434�36�_0�0 <UN> Codex Reseniani 213 1. Ætates mundi Supputatas per Judices Israeliticos, Reges Judæorum, Per- sarum, et Ægyptorum, Imperatores Romanos et Pontifices Romanos. 2. Pauca qvædam de Imperatoribus Germanicis. 3. Annales ab An. Christ. 230. ad An. 1295 continentes varia Danica, Nor- vegica, Svecica, Islandica, et Grönlandica. 4. Præcepta qvædam Geometrica. 5. Mappam Geographicam totius orbis tunc temporis cogniti. 6. Breviarium Vitæ Gudmundi Episcopi Holensis in Islandia. 7. Fragmentum Carminis cujusdam Anonymi de Magno Norvegiæ Rege Laga-bæter: Legum restauratore dicto. 8. Astronomica qvædam de cursu syderum. 9. Genealogiam majorum Odini nec on ab eo deducta stemmata et Suc- cessiones Regum Occidentalium, Saxonum, Cantianorum, Dierorum, Anglorum, Danorum usqve ad Regnerum Lodbrog/Svecorum usqve ad Haraldum Pulchricomum, Regulorum et Comitum Norvegorum usqve ad Haqvinum Haqvini apostatæ Nepotem: Deinde à Regnero Lodbrog Descendentia Stemmata Regum Daniæ usqve ad Ericum Glipping: Nor- vegiæ usqve ad Magnum Smeck; Sveciæ usqve ad Birgerum Magni filium. 10. Schema de Ecclipsibus. 11. Kalendarium Latinum. 12. Præcepta Arithmetica. 13. Varia Computum Ecclesiasticum concernentia.1 [An Icelandic membrane manuscript containing: 1. Ages of the World divided into Jewish judges, kings of the Jews, Persians and Egyptians, Roman emperors and Roman popes. 2. A smattering about the German emperors. 3. Annals from ad 230 to the year 1295 containing various items concerning Denmark, Norway, Sweden, Iceland and Greenland. 4. Some geometrical precepts. 5. A geographic map of the whole world known at that time. 6. A short Life of Guðmundr, bishop at Hólar in Iceland. 7. A fragment of an anonymous poem about King Magnús of Norway, called the Law-mender. 8. Some astronomical notes on the course of the stars. 1 Petri Johannis Resenii Bibliotheca Regiœ academiœ Hafniensi donata cui præfixa est ejusdem Resenii vita: 371. <UN>.