Let's go back to $1866.$ The Ottoman Foreign Minister Fuad Pasha wants to send $10,000$ pieces of gold to his Ambassador in Vienna, Sadullah Bey. Although the two capitals $($Istanbul and Vienna$)$ are connected by telegraph, there is no railway connection. So directly sending $10,000$ pieces of gold will involve a horse drawn carriage with armed escorts. This is very costly$.$ Thus Fuad Pasha decides to ask the assistance of his friend Mr$.$ Gaston Auboyneau, the Head of the newly founded Banque Imperiale Ottomane $($BIO$).($Obviiously the bank will charge a fee but it is much cheaper.$)$ Thus the Pasha gives $10,000$ pieces of gold $(+$ the small fee$)$ to Mr$.$ Auboyneau and asks him to forward it to Sadullah Bey in Vienna. How can this be done WITHOUT physically sending $10,000$ pieces of gold?

Note $1$: Although sending gold is expensive, sending paper is not. Sending info via telegraph is even cheaper and quicker.

Note $2$: Of course there is trade between the Ottoman and Austrian Empires, and it just so happens an Ottoman exporter from Istanbul has shipped goods worth $10,000$ pieces of gold to a Viennese importer.