The Three Barons Timeline and Summary

The three barons threaten to leave Mark's court and go to war against him if he refuses to banish Tristan from the kingdom. They tell Mark about Tristan and Yseut's adultery.
The barons enlist Frocin to help them catch Tristan and Yseut together. They seize Tristan and the queen when Tristan's blood provides evidence of their adultery.
Governal kills one of the barons as he is hunting in the forest (although he mysteriously appears again later, alive).
When Tristan asks Mark to allow him and Yseut to return to court, the barons counsel him to accept Yseut but send Tristan away.
After Yseut's return, the barons insist that Yseut clear herself of the charge of adultery, but they back off when Mark becomes angry with them.
Tipped off by a spy, the three barons attempt to catch Tristan in Yseut's bedchamber. Tristan kills two of them when their shadows give them away.