I can never look at Dagmar as a young woman (she had a very cute little face, by the way) without thinking of the tragedy of her later life as the Dowager Empress Marie. Of course she had sorrows in her early life too, her fiance's death must have been a great blow. Thyra had a baby by a young officer, didn't she?
It was the death of Georg Wilhelm that brought Ernst-August to the Court in Berlin and the meeting with Viktoria, wasn't it? Apparently Viktoria was both spoiled and strong-minded. As the only daughter she could twist the Kaiser, her father, round her little finger!
Indeed, you are correct.
It was also a controversy on the other side.
Georg V, the father in law of Thyra, supported Austria in the Diet of the German Confederation in June 1866. He refused, contrary to the wishes of his parliament to assent to the Prussian demand that Hanover should observe an unarmed neutrality during the Austro-Prussian War. As a result, the Prussian army occupied Hanover and the Hanoverian army surrendered on 29 June 1866, the King and royal family having fled to Austria. The Prussian government formally annexed Hanover on 20 September, but the deposed King never renounced his rights to the throne nor acknowledged Prussia's actions. From exile in Gmunden, Austria, he appealed in vain for the European great powers to intervene on behalf of Hanover.
Prince Ernest Augustus of Hanover (= the husband off Thyra), was born at Hanover during the reign of his paternal grandfather, Ernest Augustus I. He became the crown prince of Hanover upon his father's ascension as George V in November 1851. William I of Prussia and his minister-president Otto von Bismarck deposed George V and annexed Hanover after George sided with the defeated Austria in the 1866 Austro-Prussian War. During that war, the Crown Prince saw action at the Battle of Langensalza.
So the family of Hanover lost their throne through actions of the Prussian Royal Family. And then the grandson of the king who lost the throne wants to marry a princess from the Prussian Royal Family...............
Ernst-August (the father) was partially reconciled with the Hohenzollern dynasty in 1913, when his surviving son, Ernst August, married the only daughter of the German Emperor Wilhelm II, the grandson of the Prussian king who had deposed his father. He renounced his succession rights to the Brunswick duchy (which had belonged to the Guelph dynasty since 1235) on 24 October 1913. In exchange, the younger Ernst August became the reigning Duke of Brunswick on 1 November. William II created the elder Ernst August a Knight of the Order of the Black Eagle. In 1918 the younger Duke Ernst August abdicated his throne along with the other German princes when all the German dynasties were disestablished by the successor German provisional Government which was established when the Emperor himself abdicated and fled Germany in exile to the Netherlands.