You have 867 then a massive span of 200 years to 1066 with multiple bookmarks in that same year.
Yet there is no 876 Siege of Paris by Rollo and the Normans for a claim on Normandy?
I wish you guys would have a Normandy bookmark with the leader having claims on Sicily and other italian holdings.
It would be awesome to play the Normans, not Norman England.
Also, trying to do this manually as a random Norse warlord preparing an invasion on West Francia for Normandy won't work.
When you Prepare Invasion of West Francia and declare war, the option for Normandy doesn't show up and I'm not sure if this is because there is already a scripted event for it to happen by an adventurer or what but you as the player cannot declare war for the Duchy of Normandy and it annoys me.
There are two separate sieges of Paris by the Norse for 845 AD and 885-6 AD. If you roll forward from the 867 bookmark you might be able to get the 885 setup although not necessarily the siege itself. But going backwards isn't possible with HIP since it doesn't support a earlier date than 867 AD.
You might be able to do so with a non-HIP game by either rolling forward the date from the 769 bookmark or backwards from the 867 bookmark. There's arrows around the date at the top middle of the screen that let you go forward or backwards in the timeline from a selected bookmark - that's how I was able to play Isabella Taillefer after John Lackland's death simply by rolling from the closest bookmark to John's death date and choosing the Countess of Angouleme (she's the countess of that county in her own right)