SortStack #30 — 2026-07-09

By year · Order from earliest to most recent.

1. Charlemagne is crowned Emperor of the Romans in St. Peter's Basilica 800

   Pope Leo III crowned him on Christmas Day, reportedly taking Charlemagne by surprise — reviving the idea of a Roman emperor in the west after three centuries.

2. Constantinople falls to the Ottoman army of Mehmed the Conqueror 1453

   The Ottomans breached walls that had stood for a thousand years using enormous cannons — built by Orban, a Hungarian engineer who had first offered his services to the Byzantines.

3. Britain passes the act abolishing slavery across most of its empire 1833

   The government borrowed a colossal sum to compensate slave owners — not the enslaved. The loan was so large it was only fully paid off in 2015.

4. Archduke Franz Ferdinand is assassinated in Sarajevo, triggering the First World War 1914

   The archduke's driver took a wrong turn and stalled directly in front of Gavrilo Princip, handing the assassin a second chance after the morning's bomb attempt failed.

5. Christiaan Barnard performs the first human heart transplant in Cape Town 1967

   The first patient lived eighteen days. Barnard's second transplant patient lived more than eighteen months, proving the operation could work.

6. Nelson Mandela walks free after twenty-seven years in prison 1990

   Four years after his release he was elected South Africa's president — and he later joked that he was 'a pensioner taking up a new job' at age 75.

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