Child of: Gorm den Gamle & Thyra
The book "Danmarks dronninger i tusind år" mentions Gunhild and Tove as Harald's queens.
Sven Tveskæg & Gunhild
985, 986 or 987.
Throne passed to:
Sven 2. Tveskæg
The Bluetooth technology was named for him - ie. the bluetooth sign is the rune sign of Harald, alledgedly.