Historical eventDecember 17942

William Longsword

William Longsword of Normandy was ambushed and assassinated by supporters of Arnulf I, Count of Flanders, while both were at a peace conference to settle their differences.

Everything on December 17Original source

In context

When
Saturday, December 17 9421084 years ago
Category
Historical eventA dated happening — a battle, treaty, launch, discovery, disaster or decision — recorded on this calendar day.
Era
10th century · 940s
Calendar
Julian — as recorded at the time
Recorded from
Wikipedia “On this day” feed

Dates before 15 October 1582 are in the Julian calendar, so the weekday shown follows the Julian reckoning of the time.

At a glance

Dates: From 942.

What happened

William Longsword of Normandy was ambushed and assassinated by supporters of Arnulf I, Count of Flanders, while both were at a peace conference to settle their differences.

December 17 through the years

Other entries on the same calendar day, in order.

  1. 942William Longsword
  2. 2003SpaceShipOne
  3. 2003Soham murders
  4. 2003International Day to End Violence Against Sex Workers
  5. 2005World Trade Organization
  6. 2005Jigme Singye Wangchuck
  7. 2009MV Danny F II
  8. 2010Arab Spring
  9. 2010Mohamed Bouazizi
  10. 2014Cuba–United States relations
  11. 20162016 Irkutsk mass methanol poisoning

Sources

Cite this page

“William Longsword”, What's On This Date, https://whatsonthisdate.com/app/event/william-longsword-942-december-17, accessed October 28, 2026.

Cite the underlying source as well — the source links above go to the record this entry is adapted from.

Questions about this entry

When did William Longsword happen?

December 17 942 — 1084 years ago, on a Saturday.

Is this a Julian or a Gregorian date?

It is the date as recorded at the time, on the Julian calendar. The Gregorian equivalent falls about ten days later; sources from different countries may give either.

Where does this text come from?

Wikipedia “On this day” feed. Summaries are short adaptations that link back to the source, not reprints.

How do I cite this page?

Use the ready-made citation near the sources at the bottom of the page, and follow the source link to cite the underlying record as well.

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