How was the king wounded in season one of Game of Thrones?

King Robert Baratheon died from the injuries inflicted by a boar during a hunting accident. The wine he had been drinking had been replaced by a much stronger one, making him less aware of the dangers. The people accompanying him will surely have been instructed to let him put himself in a dangerous position - they would assassinate him by another 'accident' if they had to.

King Robert was poisoned by a conspiracy formed by his wife and killed by a wild boar when he was slowed by the poison.