I was reading about William Marshal and came accross this interesting quote:
At that time tournaments were dangerous, often deadly, staged battles, not the jousting contests that would come later, and money and valuable prizes could be won by capturing and ransoming opponents, their horses and armour. (Abels, Dr. Richard. Medieval Chivalry, The United States Naval Academy. Accessed 8 February 2012.)
were tournaments really deadly affairs where victors could ransom the losers? How would a tournament like this play out? What were the events?
In some ways the 'original' tournaments were both more and less dangerous than the solely jousting events which followed them. William the Marshal's time saw this transition in popularity.
The centerpiece of a tournament would be a battle, fought in largely open terrain, between two bands or 'companies' of knights. The draw of such events was huge and you could expect participants to come from any of the large tournaments centres, particularly France, England, Germany and even further afield. After a preliminary charge the combat would revert to general, open warfare. It was certainly dangerous; only later in the history of the tournament did it become widely accepted that blunted weapons should be used, which meant there was a chance of severe or fatal injury.
However, as you rightly mention above, this was not the aim of a tournament in as much as ransom and plunder was the real goal. You can imagine that for a young knight, on a northern French tournament field, to knock down, disarm and claim the weapons and armour of an older, established or even famous knight, was a huge incentive. It was also profitable and there was good money to be made for those who caught the eye and were rewarded for particularly brave or outlandish fighting. The ransoms paid for the losing parties alone could be significant, but the victors could also ransom arms, attire and horses etc back to vanquished enemies for good sums.
Why did the tournament transition more towards jousting? For the most part it came down to opposition from the church and the European monarchies. As the papacy was making sustained appeals for military action in Palestine and Syria, tournaments increasingly looked like a frivolous expense of both energy and money from the knightly and aristocratic classes. Princes were similarly nervous about large bands of armed men traversing their lands to meet for what could often be rather drunken and unruly games. It's not hard to imagine how such things could threaten unrest. The Plantagenet kings of England under whom William the Marshal served were largely against the holding of tournaments. That is, however, apart from Richard the Lionheart, who was something of an aficionado for tournament games.
Were the pitched battles of early tournaments really more dangerous than the later jousts? Well, eventually, certain measure were taken to decrease the likelihood of severe injury in the games of open combat, such as blunting blades and lances. However, due to the mechanics of the sport, jousting was to remain inherently dangerous, as even a fall could be hugely damaging, let alone being impacted upon with a lance. It is worth noting that even in 1559 King Henry II of France was killed by a captain of his own royal bodyguard while jousting in a lavish tournament. In any 'game' meant to replicate battle, there is the potential for serious injury and death.
To get a feel for the tournament era in which the 'games' really became standardised, Jean Froissart's accounts contain several reports of tournaments and jousts.
Edit: Spelling!