Maybe you should google "Ferdinand I of Bulgaria"

Ferdinand I, born Ferdinand Maximilian Karl Leopold Maria of Saxe-Coburg and Gotha, was the second monarch of the Third Bulgarian State. Ferdinand was born on 26 February 1861 in Vienna, a German prince of the House of Saxe-Coburg and Gotha-Koháry.
On 5 October 1908 (celebrated on 22 September), Ferdinand proclaimed Bulgaria's de jure independence from the Ottoman Empire (though the country had been de facto independent since 1878). He also proclaimed Bulgaria a kingdom, and assumed the title of tsar—a deliberate nod to the rulers of the earlier Bulgarian states.
Ferdinand desired the creation of a "new Byzantium". In 1912, Ferdinand joined the other Balkan states in an assault on the Ottoman Empire to free occupied territories. He saw this war as a new crusade declaring it, "a just, great and sacred struggle of the Cross against the Crescent." Bulgaria contributed the most and also lost the greatest number of soldiers. Though the Balkan League allies had fought together against the common enemy in the First Balkan War, that was not enough to overcome their mutual rivalries. In the original documents for the Balkan League, Serbia and Greece had been pressured by Bulgaria to hand over most of Macedonia after they had freed it from Turkish rule. However Serbia and Greece, responding to popular protest, said that they would keep possession of the territories that their forces had occupied. Soon after, Bulgaria began the Second Balkan War when it invaded its recent allies Serbia and Greece to seize this territory, before being attacked itself by Romania and the Ottoman Empire. Although Bulgaria was defeated, the 1913 Treaty of Bucharest granted the Kingdom some territorial gains. A tiny area of land giving access to the Aegean Sea was secured.
On 11 October 1915, the Bulgarian army attacked Serbia after signing a treaty with Austria-Hungary and Germany stating that Bulgaria would gain the territory it sought at the expense of Serbia. While he was not an admirer of German Emperor Wilhelm II or Austrian Emperor Franz Josef I—whom he described as "that idiot, that old dotard of a Francis Joseph".—Ferdinand wanted additional territorial gains after the humiliation of the Balkan Wars. This also entailed forming an alliance with his former enemy, the Ottoman Empire.
During the initial phase of World War I, the Tsardom of Bulgaria achieved several decisive victories over its enemies and laid claim to the disputed territories of Macedonia after Serbia's defeat. For the next two years, the Bulgarian army shifted its focus towards repelling Allied advances from nearby Greece.
To save the Bulgarian monarchy after multiple military setbacks in 1918, Tsar Ferdinand abdicated in favour of his eldest son, who became Tsar Boris III on 3 October 1918. Under new leadership, Bulgaria surrendered to the Allies and, as a consequence, lost not only the additional territory it had fought for in the major conflict, but also the territory it had won after the Balkan Wars giving access to the Aegean Sea.
The Kingdom of Bulgaria was succeeded by the People's Republic of Bulgaria, under which Ferdinand's other son, Kyril, was executed. On hearing of Kyril's death he said, "Everything is collapsing around me."
Ferdinand died a broken man in Bürglass-Schlösschen on 10 September 1948 in Coburg, Germany, cradle of the Saxe-Coburg-Gotha dynasty. He was the last surviving grandchild of Louis-Philippe of France. His final wish was to be buried in Bulgaria, and for this reason his coffin was temporarily placed in the crypt of St. Augustin, Coburg, next to his parents' coffins.
I think that's enough for any sane man or woman and even kid to understand what I had to say. His two sons were killed. Tsar Boris, his other son also died, poisoned by the Russians. He gave his two children for Bulgaria.
