why was 1672 the disaster year?
In the Franco-Dutch War and the Third Anglo-Dutch War the Netherlands was invaded by France and its allies.
William III of England
For the Dutch Republic, 1672 proved calamitous. It became known as the "Rampjaar" ("disaster year"), because in the Franco-Dutch War and the Third Anglo-Dutch War the Netherlands was invaded by France and its allies: England, Münster, and Cologne. 
who is william iii of england? sovereign Prince; Stadtholder; King of England, Ireland and Scotland has he won any battle? Yes - Battle of the Boyne
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William III of England [SEP] "Disaster year": 1672
For the Dutch Republic, 1672 proved calamitous. It became known as the "Rampjaar" ("disaster year"), because in the Franco-Dutch War and the Third Anglo-Dutch War the Netherlands was invaded by France and its allies: England, Münster, and Cologne. Although the Anglo-French fleet was disabled by the Battle of Solebay, in June the French army quickly overran the provinces of Gelderland and Utrecht. On 14 June, William withdrew with the remnants of his field army into Holland, where the States had ordered the flooding of the Dutch Water Line on 8 June. Louis XIV of France, believing the war was over, began negotiations to extract as large a sum of money from the Dutch as possible.