September 1066, King Harald of Norway invaded England from River Tees. His army had a quick successful raids around the area. Then they march forward and met Harold Godwinson's army at Stanford Bridge. Harold's archer killed King Harald with an arrow to his throat. Later his army is defeated and receded back to Norway which marked the end of Viking Era.
Coincidently Gunko has the Arrow Arrow no Mi that matches the weapon that killed King Harald of Norway. I supposed Gunko was assigned the mission to deal with Harald's 'incompetence'. Gunko travelled to the castle with government ship, not by portal because Shanks and Gaban could senses it. She went there to discuss about affiliating with World Government that led to a heated disagreement. So Gunko controlled the soldier to kill Harald. It was supposed to be a secret meeting but she didn't know Harald had summoned Loki and Jarul to the castle. That's what Loki saw in the flashback.
Coincidently Gunko has the Arrow Arrow no Mi that matches the weapon that killed King Harald of Norway. I supposed Gunko was assigned the mission to deal with Harald's 'incompetence'. Gunko travelled to the castle with government ship, not by portal because Shanks and Gaban could senses it. She went there to discuss about affiliating with World Government that led to a heated disagreement. So Gunko controlled the soldier to kill Harald. It was supposed to be a secret meeting but she didn't know Harald had summoned Loki and Jarul to the castle. That's what Loki saw in the flashback.