Conversation so far:
Are there any other interesting aspects about Hrólfr Kraki?
Hrólfr Kraki appears in both Anglo-Saxon and Scandinavian tradition.
Who are the two sons of Haldan and what did they do?
Ro (Hroðgar) and Helgo (Halga) were the son of Haldan (Healfdene). When Haldan died of old age, they divided the Kingdom.
What are the exploits of the sons Helga and Ro?
One day, Helghe arrived in Halland/Lolland.
What happened to Helghe after he arrived in Halland?
Helghe slept with Thore, the daughter of one of Ro's farmers. This resulted in a daughter named Yrse.
What happened to the other son Ro?
Ro founded and gave his name to the market town of Roskilde.
Are there any other interesting aspects about Hrólfr Kraki?
Hrólfr Kraki was a legendary Danish king who appears in both Anglo-Saxon and Scandinavian tradition.

Question: What did the Swedish king do?
Self-contained rewrite: What did the Swedish king in the Hrólfr Kraki legend do?