Summary from Wikipedia

The son of Victor Emmanuel II and Adelaide of Austria, Umberto took part in the Italian Wars of Independence as a commander of the Royal Sardinian Army. He assumed the Italian throne in 1878 on the death of his father. A strong militarist, Umberto approved the alliance with Germany and Austria-Hungary, which was formalised in 1882. He also encouraged Italy's colonial efforts and oversaw the incorporation of Eritrea and Somalia into the Italian Empire.