The Upsala Codex, a parchment document from about 1330, is one of the most important manuscripts of the Prose Edda, or so-called "Younger Edda", which was written by Snorri Sturluson around 1220 CE. It has four sections.
The first part, The Prologue, consists of anthropological observations, which justify Snorri's retelling of the mythological tales. Snorri has used an orthodox Christian stance, identifying the pagan gods as ancient heroes deified by their ignorant followers. He explains the mythology as a the remnants of the history of a royal dynasty in Asia. (This may not be totally off the mark, given the evidence of runic alphabets found in Hungary and Turkey.)
In the beginning almighty God created heaven and earth and everything that goes with them and, last of all, two human beings, Adam and Eve, from whom have come families. Their progeny multiplied and spread over all the world. As time went on, however, inequalities sprang up amongst peoples - some were good and righteous but by far the greater number, disregarding God's commandments, turned to the lusts of the world. For this reason God drowned the world and all creatures living in it - with the exception of those who were with Noah in the ark.
Eight persons survived Noah's flood and these peopled the world and founded families. As the population of the world increased, however, and a larger area became inhabited, the same thing happened again; the great majority of mankind, loving the pursuit of money and power, left off paying homage to God. This grew to such a pitch that they boycotted any reference to God, and then how could anyone tell their sons about the marvels connected with Him In the end they lost the very name of God and there was not to be found in all the world a man who knew his Maker.
Notwithstanding, God granted them earthly gifts, worldly wealth and prosperity, and He also bestowed on them wisdom so that they understood all earthly things and all the ways in which earth and sky were different from each other. They observed that in many respects the earth and birds and beasts have the same nature and yet exhibit different behavior, and they wondered what this signified.
For instance, one could dig down into the earth on a mountain peak no deeper than one would in a low lying valley and yet strike water; in the same way, in both birds and beasts, the blood lies as near to the surface of the skin of the head as of the foot. Another characteristic of the earth is that every year grass and flowers grow on it and that same year wither and die; similarly fur and feathers grow and die every year on beasts and birds. There is a third thing about the earth: when its surface is broken into and dug up, grass grows on the topsoil. Mountains and boulders they associated with the teeth and bones of living creatures, and so they looked on earth as in some way a living being with a life of its own. They knew it was inconceivably ancient as years go, and by nature, powerful; it gave birth to all things and owned all that died, and for that reason they gave it a name and reckoned their descent from it.
They also learned from their ancestors that the same earth and sun and stars had been in existence for many centuries, but that the procession of the stars was unequal; some had a long journey, others a short one. From things like this they guessed that there must be someone who ruled the stars, who, if he desired, could put an end to their procession, and that he must be very powerful and strong. They reckoned too, that, if he controlled the primal elements, he must have existed before the heavenly bodies; and they realized that, if he guided these, he must rule over the shining of the sun and the dew-fall and the growth of plants resultant on these, and the winds of the air and storms of the sea as well.
They did not know where his kingdom was, but they believed that he ruled everything on earth and in the sky, heaven and the stars, the ocean and all weathers. In order that this might be related and kept in mind, they gave their own names to everything, but with the migrations of peoples and multiplication of languages this belief has changed in many ways.
They understood everything in a material sense, however, since they had not been given spiritual understanding, and so they thought that everything had been made from some substance.
The world was divided into three parts. From south to west up to the Mediterranean was the part known as Africa, and the southern portion of this is so hot that everything there is burned by the sun. The second part, running from west to north up to the ocean, is called Europe or Énéa, and the northern half of this is so cold that no grass grows there and it is uninhabited. From north to east and down to the south is Asia, and these regions of the world have great beauty and magnificence; the earth yields special products like gold and precious stones. The center of the world is there also, and just as the earth there is more fertile and in every way superior to that found elsewhere, so the human beings living there were endowed beyond their fellows with all manner of gifts - wisdom, strength, beauty and every kind of ability.
Near the center of the world where what we call Turkey lies, was built the most famous of all palaces and halls - Troy by name. That town was built on a much larger scale than others then in existence and in many ways with greater skill, so lavishly was it equipped. There were twelve kingdoms with one over-king, and each kingdom contained many peoples. In the citadel were twelve chieftains and these excelled other men then living in every human fashion.
One of the kings was called Múnón or Mennón. He married a daughter of the chief king Priam who was called Tróáin, and they had a son named Trór - we call him Thór. He was brought up in Thrace by a duke called Loricus and, when he was ten years old, he received his father's arms. When he took his place amongst other men he was as beautiful to look at as ivory inlaid in oak; his hair was lovelier than gold. At twelve years old he had come to his full strength and then he lifted ten bear pelts from the ground at once and killed his foster father Loricus with his wife Lóri or Glóri, and took possession of the realm of Thrace - we call that Thrúdheim.
After that he traveled far and wide exploring all the regions of the world and by himself overcoming all the berserks and giants and an enormous dragon and many wild beasts. In the northern part of the world he met with and married a prophetess called Sibyl whom we call Sif . I do not know Sif's genealogy but she was a most beautiful woman with hair like gold. Lóridi, who resembled his father, was their son. Lóridi's son was Einridi, his son Vingethór, his son Vingener, his son Módi, his son Magi, his son Seskef, his son Bedvig, his son Athra, whom we call Annar, his son Ítrmann, his son Heremód, his son Skjaldun, whom we call Skjöld, his son Bíaf whom we call Bjár, his son Ját, his son Gudólf, his son Finn, his son Fríallaf whom we call Fridleif; he had a son named Vóden whom we call Odin; he was a man famed for his wisdom and every kind of accomplishment. His wife was called Frígída, whom we call Frigg.
Odin, and also his wife, had the gift of prophecy, and by means of this magic art he discovered that his name would be famous in the northern part of the world and honored above that of all kings. For this reason he decided to set out on a journey from Turkey. He was accompanied by a great host of old and young, men and women, and they had with them many valuables. Through whatever lands they went such glorious exploits were related of them that they were looked on as gods rather than men. They did not halt on their journey until they came to the north of the country now called Germany.
There Ódin lived for a long time taking possession of much of the land and appointing three of his sons to defend it. One was called Vegdeg; he was a powerful king and ruled over East Germany; his son was Vitrgils; his sons were Vitta, father of Heingest, and Sigar, father of Svebdag, whom we call Svipdag. Odin's second son was called Beldeg, whom we call Baldr; he had the country now called Westphalia; his son was Brand; his son, Frjódigar, whom we call Fródi; his son, Freóvin; his son, Wigg; his son, Gevis, whom we call Gave. Odin's third son was called Sigi; his son, Rerir; this pair ruled over what is now called France, and the family known as Völsungar come from there. Great and numerous kindreds have come from all of them. Then Odin set off on his journey north and coming to the land called Reidgotaland took possession of everything he wanted in that country. He appointed his son Skjöld to govern there; his son was Fridleif; from thence has come the family known as Skjöldungar; they are kings of Denmark and what was then called Reidgotaland is now named Judand.
Thereafter Odin went north to what is now called Sweden. There was a king there called Gylfi and, when he heard of the expedition of the men of Asia, as the Æsir were called, he went to meet them and offered Odin as much authority over his kingdom as he himself desired. Their travels were attended by such prosperity that, wherever they stayed in a country, that region enjoyed good harvests and peace, and everyone believed that they caused this, since the native inhabitants had never seen any other people like them for good looks and intelligence.
The plains and natural resources of life in Sweden struck Odin as being favorable and he chose there for himself a townsite now called Sigtuna. There he appointed chieftains after the pattern of Troy, establishing twelve rulers to administer the laws of the land, and he drew up a code of law like that which had held in Troy and to which the Trojans had been accustomed.
After that, he traveled north until he reached the sea, which they thought encircled the whole world, and placed his son over the kingdom now called Norway. Their son was called Saeming and, as it says in the Háleygjatal, together with the earls and other rulers the kings of Norway trace their genealogies back to him.
Odin kept by him the son called Yngvi, who was king of Sweden after him, and from him have come the families known as Ynglingar. The Æsir and some of their sons married with the women of the lands they settled, and their families became so numerous in Germany and thence over the north that their language, that of the men of Asia, became the language proper to all these countries. From the fact that their genealogies are written down, men suppose that these names came along with this language, and that it was brought here to the north of the world, to Norway, Sweden, Denmark and Germany, by the Æsir. In England, however, there are ancient district and place names which must be understood as deriving from a different language.
[I do not recall where I found this translation of the Prologue. I assume that it is in the public domain If you recognize it and know the author, please let me know.. Sunny}