On March 12, 1171, the Byzantine emperor ordered a shocking crackdown, rounding up over 20,000 Venetians in Constantinople and seizing their property. This brutal attack on Venice’s merchant class forced the Republic to seek revenge. To fund a massive fleet, Doge Vitale II needed a huge sum of cash. He divided the city into six districts, assessed citizens’ wealth, and forced them to loan money to the state. The loans, called prestiti, paid 5% interest yearly, but the real breakthrough was making the receipts tradable. If a citizen needed cash, they could sell their loan slip at the Rialto market. The revenge expedition was a disaster, hit by plague and stalled negotiations, and the doge was ultimately murdered by an angry mob back in Venice. But the debt remained. Venice couldn’t pay it back, so it became a permanent obligation. Because the interest was reliable and the slips were tradeable, the Rialto became the world’s first bond market, turning a symbol of national shame into the foundation of modern finance.
