What brought about WW1 and 2?

Answer 1

The proximate reason for WWI was the assassination of Archduke Ferdinand by Gavrilo Princip. Princip assassinated Ferdinand in the hope of liberating Bosnia-Herzegovina from Austria-Hungary and then having Serbia join in a union with Bosnia-Herzegovina so as to escaped domination from the Ottoman Empire.

However, the roots for the 1914 assassination of Ferdinand in Sarajevo were laid from a chain of events that began with the 1875 Bosnian insurrection against Muslim Ottoman Turkey which had conquered Bosnia in the mid 1400s as part of the expansion of the Islamic Caliphate.

Prior to the start of WW1 there'd been 2 Balkan Wars. The 1st Balkan War was fought between the members of the Balkan League; Serbia, Bulgaria, Greece, and Montenegro; and the Ottoman Empire as the Muslim Turks considered their Christian subjects as dhimis, 2nd class citizens. The 2nd Balkan War left a bitter legacy between Serbia and Austria.

With the assassination of the Archduke the assassins were counting on a war between Serbia and Austria which would bring in Orthodox Christian Czarist Russia on Serbia's side resulting in a regional war, thus driving out the last remnant of the Muslim Ottoman Caliphate. However, due to interlocking treaties the war evolved into a worldwide conflagration. With Austria declaring war on Serbia and Russia coming to Serbia's aid, Germany as an ally of Austria, and Italy, joined in against Russia. Germany attacked France as France was an ally or Russia. With the attack on France, her ally Great Britain became involved. Finally, due to its aid to Great Britain the Germans attacked US shipping and the USA became involved on Britain's, France's, and Russia's side.

The real roots of the conflict were laid down by the Islamic expansion into most of Europe and the Middle East which resulted in the Crusades to gain back formerly European lands. However, after the Crusades there were European lands still under the Caliphate's rule and intense bickering and wars in Europe over jockeying for supremacy in a revised Holy Roman Empire.

With the enforced and unfair peace on a Germany that was never invaded by the Allies the roots for Hitler and WW II were laid. Due to the unfair peace essential parts of Germany, including German people, were given to other nations. It was Hitler's desire to reunite the German people and to regain German industrial and mining regions that led to WW II.