Since his crowning of King of the Belgians King Leopold aquired considrable influence over Belgian politics.
In june 1855 the Belgium army crossed the border with the Netherlands in a suprise attck on its Northern neigbor.
The attack was conceived by Leopold long time ago when he was 19 years old and only crown prince.
The attack, preceded by carefull planning and inellengence was an all out succes.
The Dutch army no match for the larger and better organised Belgium army. The Belgium army advanced rapidlt through Brabant and crossed after encountering some resistance the river Waal. The Dutch army was in desarray and only small units of the field army gave fierce resistance, how ever they had to give way due to the larger opponents. The whole advance was so sudden and swift that the Dutch hardly had time to organised seriuos resistance.
Within 4 days the Belgian army occupied The Hague and offered terms of surrender at the Dutch Cabinet.
Despite the military victory, an Catholic uprising or simpathy, as anticipated by Leopold did not materialise. On the contrary, population, Protestant and Catholic was hostile towards the troops and on several places riots and open fighting broke out between Belgian soldiers and civilians.
The Great Powers were stuned by the move of Belgium and dissaproved the whole action, however the Dutch defence colapsed so swift that there was no time to organise any diplomatic or military support to the Dutch.
Great Brittain and Prusia offerd to mediate between the two countries monitored by France.
The Netherlands would cede the Provinces Brabant and Limburg and Zeeuws Vlanderen. This would shift the border to the river Maas
and provide the Belgians control of on bank of the river Schelde.
There were also demands for war reparations and the demand for Sumatra or Borneo but due to diplomatic presure of the Great powers this did not materialise.
The Grea Powers on their hand regarded the London treaty of 1839 as obsolete and did not reagrded Belguim neutral.
By 1869 Leopold was probed if he was interested in a secret defence agrement with Prusia, which he was.
When in 1870, at all a sudden France declared war to Prusia an it allies, the Belgium army made it self ready, for the record just to defend the country. When fighting was goiing on and the French were already in the defence, the Belgian field army crossed the French border and occupied the teritory up to the river Somme. When finaly hostilities ended Franche ceded to Belgium the departments Pas de Callais and Flandre du Nord. The were incorporated in the Belgium province Flandres and a new province Arras.
In the next years, Leopold still wanting to have a place under the sun, involved him self with the exploration of the Congo bassin, resulting at the Berlin conference with an enormous piece of real astate in the centre of the African continent.
At the end of his life he made Belgium double in size and made it an colonial power as well.
How ever the Belgian state even highly industrialised was forced to maintain a large amry and even a serious Navy to oppose any threats of the Great Powers, since it was considered in diplomatic circles as an unrilaible partner.