▁over ▁ 1 6 2 5 – 2 7 , ▁at ▁first ▁against ▁Mans feld . ▁ ▁Having ▁be aten ▁Mans feld ▁at ▁D ess au ▁( 2 5 ▁April ▁ 1 6 2 6 ), ▁W allen stein ▁cleared ▁S iles ia ▁of ▁the ▁rem n ants ▁of ▁Mans feld ' s ▁army ▁in ▁ 1 6 2 7 . ▁ ▁At ▁this ▁time ▁he ▁bought ▁from ▁the ▁em peror ▁the ▁Duch y ▁of ▁S agan ▁( in ▁S iles ia ). ▁He ▁then ▁joined ▁T illy ▁in ▁the ▁struggle ▁against ▁Christian ▁IV ▁of ▁Den mark , ▁and ▁afterwards ▁gained ▁as ▁a ▁reward ▁the ▁Duch ies ▁of ▁Me ck len burg , ▁whose ▁her edit ary ▁du kes ▁suffered ▁exp ulsion ▁for ▁having ▁helped ▁the ▁Dan ish ▁king . ▁This ▁award ing ▁of ▁a ▁major ▁territory ▁to ▁someone ▁of ▁the ▁lower ▁nob ility ▁shock ed ▁the ▁high - born ▁r ul ers ▁of ▁many ▁other ▁German ▁states . ▁ ▁W allen stein ▁assumed ▁the ▁title ▁of ▁" Ad mir al ▁of ▁the ▁North ▁and ▁Balt ic ▁Se as ". ▁However , ▁in ▁ 1 6 2 8 ▁he ▁failed ▁to ▁capture ▁Str als und , ▁which ▁resist ed ▁the ▁Capit ulation ▁of ▁Franz burg ▁and ▁the ▁subsequent ▁sie ge ▁with ▁assistance ▁of ▁Dan ish , ▁Scottish ▁and ▁Swedish ▁troops , ▁a ▁blow ▁that ▁denied ▁him ▁access ▁to ▁the ▁Balt ic ▁and ▁the ▁chance ▁to ▁challenge ▁the ▁naval ▁power ▁of ▁the ▁Sc and in av ian ▁kingdom s ▁and ▁of ▁the ▁Netherlands .