Tuhia he tomokanga mō tēnei wāhanga - Kia pōtitia ai a Frederick hei kingi i muri i te matenga o tōna pāpā, ka tukua e ia he mana nui ki te hunga rangatira. I a ia e kingi ana, e rua nga pakanga i whawhai ai ia ki a Sweden. I hinga ia i te Pakanga Danish-Swedish o te 1657<unk>1658, engari i tino rongonui ia i te wa i whakaekea ai e ia te 1659 Te whakaeke ki Copenhagen
I wikitoria ia i te Pakanga o Denmark-Sweden o te tau 1658<unk>1660. I muri mai i taua tau, i whakamahia e Frederick tana rongonui ki te whakakore i te rangatiratanga pooti hei painga mo te rangatiratanga tino, i roa tae noa ki te 1848 i Denmark. I marenatia ia ki a Sophie Amalie o Brunswick-Lüneburg, nana nei i whanau a Christian V o Denmark.