The Battle of Olšava was an engagement of Bohemian and Hungarian troops near the Olšava River along the frontier of the two realms in May 1116. The event started as a peaceful meeting between the young Stephen II of Hungary and Vladislaus I of Bohemia, according to Hungarian chronicles. The Czech Cosmas of Prague wrote that the Hungarians came to the border to provocate a war.
Fetching the article from Wikipedia…
Text from the Wikipedia article “Battle of Olšava”, available under CC BY-SA 4.0.