What we only found is that "Spear-Danes" are the Scyldings (the tribe which Hrothgar belongs to) - central characters in Beowulf.
They are variously referred to as Beorht-Dene (Bright-Danes), Éast-Dene (East-Danes), Gár-Dene (Spear-Danes), Hring-Dene (Ring-Danes), Norð-Dene (North-Danes), Súð-Dene (South-Danes), West Dene (West Danes), Scyldings (after their eponymous founder) and Ingwine.
Beowulf is the longest epic poem in Old English, the language spoken in Anglo-Saxon England before the Norman Conquest. More than 3,000 lines long, Beowulf relates the exploits of its eponymous hero, and his successive battles with a monster named Grendel, with Grendel’s revengeful mother, and with a dragon which was guarding a hoard of treasure.
Learn more by checking these facts about Beowulf from Primaryfacts.com.