thumb|Seeschlacht bei Fehmarn, wo die schwedisch-niederländische Flotte nahezu alle dänischen Schiffe versenkte
Der '''Torstensson-Krieg''' war ein Krieg zwischen den beiden Ostseemächten Dreißigjährigen Krieges. 

Er begann am 12. Dezember 1643 ohne formelle jütländische Halbinsel. 

Im Februar 1644 rückten schwedische Truppen unter dem Kommando Gustav Horns in das dänische Schonen ein und eroberten unter anderem Helsingborg und Landskrona, während die Festungen in Malmö und Kristianstad (dänisch: ''Christiansstad'') den Angreifern Stand hielten (Dieser Teilkrieg wird auch als ''Hornkrieg'' bezeichnet.). 

Am 1. Juli 1644 leitete der dänische König Christian IV. eine ''Seeschlacht auf der Kolberger Heide'' vor der Kieler Förde, bei der er ein Auge verlor, die Schlacht aber knapp gewinnen konnte (Hierauf bezieht sich noch heute die dänische Königshymne ''Kong Kristian stod ved højen mast'').

Am 13. Oktober desselben Jahres verlor die dänische Flotte eine ''Seeschlacht zwischen Fehmarn und Lolland'' gegen eine vereinte schwedisch-niederländische Flotte. 

{{Infobox Military Conflict
|conflict= Torstenson War
|partof= Thirty Years' War
|image= 
|caption= 
|casus=Swedish attempt to break strategic encirclement
|date= 1643 - 1645
|place= Denmark, Norway, Sweden
|territory=Jämtland, Härjedalen, Gotland, parts of Älvdalen Municipality, Saaremaa and Halland (on 30 years) become Swedish territories
|result= Swedish victory
|combatant1= 20px 20px The Netherlands
|combatant2= 20px Denmark-Norway
|commander1= 20px Gustav Horn<br>20px 20px 20px Maerten Thijssen
|commander2= 20px 20px Hannibal Sehested
|strength1= 24,600
|strength2= 32,000
|casualties1=
|casualties2=
|notes=
}}

The '''Torstenson war''', '''Hannibal controversy''' or '''Hannibal War''' (Norwegian: ''Hannibalsfeiden'') was a short period of conflict between Hannibal Sehested.

==The cause==
Sweden had been highly successful in the Thirty Years’ War, having defeated Danish armies in Germany and seen substantial victories under Sound Dues were also a continuing source of irritation and a contributing factor to the war.
 
In the spring of 1643 the Swedish Privy Council determined that their military strength made territorial gains at the expense of Denmark likely. The Count drew up the plan for war and directed a surprise multiple-front attack on Denmark in May.

==The beginning==
Swedish Field Marshal Moravia, his forces entered Danish territory at Skåne and Malmø, with an army of 11,000 men.

==The Danish response==
This attack caught Denmark unaware and poorly prepared, but Christian IV retained his presence of mind. He placed his confidence in the fleet to protect the home islands and on the forces of Norway to relieve the pressures on Danish provinces in Skåne by attacking Sweden along the Norwegian-Swedish border.

==The Norwegian response==
Norway, which was then governed by Christian's son-in-law, Hannibal Sehested, was a reluctant participant. The Norwegian populace opposed an attack on Sweden, correctly suspecting that an attack on Sweden would only leave them open to counterattack. Their opposition to Statholder Sehested’s direction grew bitter, and the war was lampooned as the "Hannibal war." Understandably, the Danes cared little for Norwegian public sentiment when Denmark itself was seriously threatened. Hence Jemtland. He was driven back out of Sweden and Swedish troops temporarily occupied Jemtland as well as advancing into the Norwegian Østerdal before being driven back. 