A few days later, under the instigation and urging of Bismarck, Prussia and Austria reached an agreement.
The Austrian army continued to attack the Danes together with the Prussian army, unless the Danish government agreed to the complete independence of the two duchies.
The Danes naturally could not agree, as losing Schleswig would mean losing more than thirty percent of Danish territory, and nationalists within Denmark would surely label the cabinet as traitors.
Compared to surrendering without a fight, a defeat was more likely to draw sympathy from the Danish people; it wasn't that the government wasn't trying, but that the Germans were too despicable.
The Danish government rejected the conditions of the German states, and so the Allies' war machine started once again.
On March 8, after receiving orders from home, the Austrian Imperial Army launched the war first and won the Battle of Weiler.
On March 15, the Danish navy declared a blockade of the Prussian coast, and the navy entered the war while the newly established Prussian navy responded.
The naval fleets of both sides began a fierce exchange of fire in the Yasmond area. At that time, the Prussian navy was recently established, while Denmark was a traditional naval power in the Nordic region. Naturally, the results of the battle were self-evident, and two days later, the Danish navy achieved a tactical victory in the Battle of Yasmond.
The weak Prussian navy was no match for the Danish navy; Denmark firmly controlled sea power, but the Prussian navy retained its vitality and was not completely annihilated.
On the same day, the Prussian army also launched an offensive on the new positions set by the Danish army at Di Bo'er. Prussia initially mobilized artillery for a massive bombardment of the Di Bo'er positions, followed by an infantry assault under the cover of artillery fire.
Facing the ferocious Prussian forces, the new Danish commander naturally dared not repeat the mistakes of General Mesa. This time, they chose not to withdraw from the battlefield, and the Danes, with tenacious perseverance, repelled several probing attacks by the Prussians within a day.
However, this skirmish was merely a prelude; the Prussian army's major assault was still building strength.
A month later, on April 18, the Battle of Di Bo'er broke out. After several hours of artillery preparation, Prussia launched a full-scale attack, with hundreds of cannons simultaneously attacking the Di Bo'er positions, charging at Di Bo'er under the firepower of the Herolff anchored near the Danish coastline.
As the Danish flagship, the Herolff was clearly unable to stop the Prussians' land assault and could only slow down the Prussian army's advance.
Under the overwhelming artillery barrage, the Danes could only hide in fortifications, and the Prussians seized the moment, leveraging their manpower advantage to advance on Di Bo'er.
Gradually, the vanguard, charging at the forefront, reached the edge of the Di Bo'er positions.
Under the powerful artillery attacks of the Allied forces, the Di Bo'er positions were already on the brink of collapse, with many temporary fortifications reduced to ruins under the bombardment.
The Prussian army that reached the Di Bo'er positions successfully penetrated the Danish lines by utilizing these ruins.
Seeing the overwhelming odds, the Danish commanding officer had no choice but to order the troops to abandon Di Bo'er, leaving only the Danish Army's 8th Brigade for rear guard action.
The Danish Army's 8th Brigade resisted fiercely to cover the Danish main force's retreat.
However, they suffered heavy losses, with over a third of the Danish Army's 8th Brigade being decimated by the Prussian forces. Yet, they successfully completed the task of covering the retreat of the Danish main force.
After the defeat in the Battle of Di Bo'er, the Danish military, constrained by its forces, had to abandon actions to recapture the Fredericia area, which had already been occupied by Austrian forces.
In a series of battles by the Allied forces, almost half of the Danish territory on the Jutland Peninsula (including Schleswig) was lost. The Danish hope for victory was smothered to the point that even a spark was extinguished by the Allies.
Meanwhile, Denmark's continuous setbacks led the British government to decide to intervene; maintaining the balance of the continent was the bottom line for the British, as they couldn't allow significant changes among European countries.
Previously, the British government had already issued a stern warning to Prussia, and Prussia verbally agreed to a temporary truce on April 12.
However, Bismarck postponed this plan to April 25, during which time Prussia took control of the entire Di Bo'er.
With support from Russia, France, and Sweden, the British government suggested intervening in the Jutland Peninsula conflict, indicating that the Schleswig issue should be decided by a coalition of European countries.
Already secretly unified in opinion, Austria and Prussia stated that as long as the 1852 agreement was not used as the basis for the resolution, and that the duchies were only connected to Denmark in a personal capacity, the two countries would agree to the resolution.
The conference was held in London on April 25, chaired by the British representative, Viscount Palmston.
Britain condemned the war actions of Prussia and Austria, which threatened European peace.
However, the German representatives only indicated that the issues in question were inevitably chaotic.
At the same time, Count Boyst, representing the German Confederation, demanded that all nations recognize Augustenburg's sovereignty over the duchies.
Although the Austrian Empire leaned more toward a solution similar to the 1852 agreement, Prussia had already shown ambition to acquire the duchies.
If the Kingdom of Prussia wished to achieve this ambition, it first needed to ensure the complete independence of the Duchy of Schleswig.
Therefore, the Prussian representative insisted that the Schleswig region should be completely independent from Denmark.
This placed Austria in a dilemma: opposing might result in losing influence in the German area, but not opposing could boost Prussia's power.
After weighing the pros and cons, Austria still believed that influence in the German region was more crucial, as unifying the entire German area was also the Austrian Empire's aspiration.
Reluctantly, Austria supported Prussia's proposal for Schleswig to achieve full political independence, but it should be restricted by a joint institution, with further steps not yet considered.
To appease Britain, France, and Russia, the Prussian representative stated that Prussia would not seek territories beyond the duchies of Schleswig and Holstein.
This satisfied other major powers' requirements of not letting any other major power control the Danish straits leading to the Baltic Sea.
The Swedish representative did not express an opinion, as historically, Denmark was a competitor for Sweden. If Prussia and Austria could weaken Denmark's strength a bit, Sweden would be pleased to see it.
Of course, the premise was that the German Allies wouldn't swallow the entire Jutland Peninsula, which would pose an even more severe strategic geographical threat to Sweden than Denmark.
Obviously, neither Prussia nor Austria considered the feelings of the Danes, and other countries like Britain tacitly agreed to Prussia's conditions. The Danish government refused the proposal.
This London conference did not fundamentally resolve the Jutland Peninsula issue but temporarily slowed the offensive of Prussia and Austria.
Taking advantage of the time during the conference, the Danes completed their final mobilization, but most of the Danish military efforts on the Jutland Peninsula had already failed.
The troops moved to Als Island to continue the resistance. In June, the Prussian army began gathering opposite Als Island. The Second Schleswig War was about to enter a new phase.