Short answers, pulled from the story.
Thyra was the wife of King Gorm the Old of Denmark and is considered one of the first historically documented queens of Denmark. She likely ruled until her death in the middle of the 10th century and is remembered on at least four Viking Age runestones, more than any other person in that era.
Danmarkar bot is an Old Norse phrase inscribed on the Jelling 1 runestone that Gorm raised in Thyra's honour after her death. It translates variously as Denmark's adornment, strength, salvation, or remedy. The same term is used to describe her in the Saga Hálfdanar svarta.
Medieval sources including Saxo Grammaticus and Sven Aggesen credit Thyra with ordering the construction or fortification of the Danevirke, the system of ramparts protecting Denmark's southern border. Archaeological evidence shows the first phase of construction predates her reign, with timber felled as early as 737 CE, but Thyra is thought to have overseen a significant phase of extension.
Historians widely agree that Thyra and Gorm the Old were the parents of Harald Bluetooth, who later commissioned the Jelling 2 runestone in their honour, and most also accept that they had a son named Canute. The Historia Norwegiæ additionally claims they had a daughter, Gunnhild, Mother of Kings, but this is not corroborated by other evidence.
The northern burial mound at Jelling, known as Thyras Høj, is traditionally associated with her. When excavated, no human remains were found inside. Wooden artefacts within the mound were dated by tree-ring analysis to 959-960 CE, which is considered the latest possible date for her death if the mound is indeed hers.
Ravnunge-Tue is one of the earliest known Western European artisans to have signed his own work as the maker. Analysis of rune shape, groove depth, and spelling suggests he carved inscriptions on both the Laeborg stone and the Jelling 2 stone, linking those stones to the same Thyra. This finding supports the argument that at least four surviving runestones commemorate the same woman.