Short answers, pulled from the story.
Hedeby sat at the southern end of the Jutland Peninsula where the Schlei inlet meets the Baltic Sea. A portage route shorter than 15 kilometers connected this waterway to the Treene River and eventually the North Sea.
Charlemagne stayed at a place called Hedeby in the summer of 804 while concluding his Saxon Wars. This event marked an early period when the settlement functioned as a vital link between the Frankish Empire and Scandinavia.
Danish King Godfred destroyed the competing Slav trade center named Reric in 808 and resettled its merchants there. This event provided the initial impetus for the town's dramatic expansion into a major international trading hub.
King Harald Hardrada of Norway sacked Hedeby in 1050 during a conflict with King Sweyn II of Denmark. Burning ships were sent into the harbor leaving charred remains at the bottom of the Schlei inlet today.
Sophus Muller rediscovered the exact location of the site in 1897 after centuries of being forgotten. Archaeological work began in 1900 with small-scale excavations led by Johanna Mestorf.