Soon thereafter occurred the Sarajevo assassination of Archduke Franz Ferdinand. Ferdinand became Archduke of Austria in 1621. In 1781 the Austrian archduke, Emperor Joseph II, unilaterally renounced the treaty. That caused Russia to defend Serbia against Austria after the assassination of the Austrian Archduke. The emperor placed Charlotte under custody of his brother Archduke Karl Ludwig of Austria. The name of the band was originally inspired by a racehorse called Archduke Ferdinand. Matthias entered into an alliance with the Emperor's rebellious brother Albert VI, Archduke of Austria. In 1837, Archduke Friedrich Leopold enlisted into the Navy. The emperors retained the title of Archduke of Austria. The death of Archduke Rudolf caused a dynastic crisis. He is informally titled as an Imperial and Royal Archduke of Austria. Teniers painted 10 paintings representing the collection of the Archduke Leopold Wilhelm in Brussels. Archduke Charles was reared a devout Catholic. That day, he traveled to Innsbruck to visit the grave of Archduke Eugen of Austria. Other marriage negotiations with Sebastian of Portugal and Archduke Rudolf also did not succeed.