▁Emperor ▁Ferdinand ▁III ▁ordered ▁his ▁v ass al ▁Christ ina ▁of ▁Sweden , ▁then ▁Duch ess ▁reg nant ▁of ▁Bre men - Ver den , ▁to ▁rest itute ▁Bre mer le he ▁to ▁Bre men . ▁However , ▁Swedish ▁Bre men - Ver den ▁soon ▁en act ed ▁the ▁First ▁B rem ian ▁War ▁( M arch ▁to ▁July ▁ 1 6 5 4 ) ▁and ▁in ▁the ▁following ▁peace ▁treat y ▁( ; ▁November ▁ 1 6 5 4 ) ▁Bre men ▁had ▁to ▁c ede ▁Bre mer le he ▁and ▁its ▁surr ound ings ▁to ▁Swedish ▁Bre men - Ver den . ▁The ▁latter ▁developed ▁plans ▁to ▁found ▁a ▁fort ified ▁town ▁on ▁the ▁site , ▁and ▁much ▁later ▁this ▁location ▁became ▁the ▁present - day ▁city ▁of ▁Bre mer h aven . ▁ ▁In ▁ 1 6 7 2 , ▁under ▁the ▁reign ▁of ▁Charles ▁XI ▁of ▁Sweden , ▁in ▁personal ▁union ▁Duke ▁of ▁Bre men - Ver den — colon ists ▁tried ▁un success fully ▁to ▁ere ct ▁a ▁castle ▁( named ▁Car ls burg ▁after ▁Charles ▁XI ) ▁there ; ▁this ▁fort ified ▁structure ▁was ▁meant ▁to ▁protect , ▁as ▁well ▁as ▁control ▁sh ipping ▁heading ▁for ▁Bre men . ▁ ▁Finally , ▁in ▁ 1 8 2 7 , ▁the ▁city ▁of ▁Bre men ▁under ▁Burg om aster ▁Johann ▁Sm id t ▁bought ▁the ▁territ ories ▁at ▁the ▁mouth ▁of ▁the ▁Wes er ▁from ▁the ▁Kingdom ▁of ▁Han over . ▁Bre men ▁sought ▁this ▁territory ▁to ▁retain