Whakaotihia te rerenga e whai ake nei: I muri i te matenga o tona papa, i whiriwhiria a Frederick hei kingi, i whakaaetia e ia he mana nui ki nga rangatira. I a ia e kingi ana, e rua nga pakanga i whawhai ai ia ki a Sweden. I hinga ia i te Pakanga o Denmark-Swedish o te 1657<unk>1658, engari i tino rongonui ia i te wa i ora ai ia i te
1659 Te whakaekenga o Copenhagen me te wikitoria i te Pakanga Danish-Swedish o 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.