This amazing and rare weapon is a long seax / scramasax / sword (as per its dimenstions) based on several exemplars clasified by Petersen as Type G swords.
The most similar archaeological find is the sword found at Dale, Oppland, Norway. Dating this Type G swords is pretty ambiguous, being probably the most accurate from the end of 8th to 9th century.
It basically presents a guard which matches the pommel, which present symetrical curled ends, twisted in spirals or volutes. The sword does not present any other decoration and the blade is single edged, with a wide fuller.
Details:
Specs may slightly vary from piece to piece.
This typology was not very common during Viking Age, and that's because the information regarding this sword is so limited. If you want to know more about this sword, visit the fantastic research work made by Projekt Forlǫg.