"古代北欧文字" can be translated into English as "Ancient Nordic runes" or "Old Norse runes".
"Ancient Nordic runes" emphasizes the historical and geographical context (Nordic region), while "runes" specifically refers to the ancient alphabet used.
"Old Norse runes" highlights the language association ("Old Norse" being the ancient Germanic language spoken in Scandinavia), making it equally valid if the focus is on the linguistic or cultural aspect.
Both terms are widely accepted, depending on the nuance you wish to convey.