Here is the full list of all 37 Ancestors Legacy achievements worth 1,000 gamerscore.
Complete the mission 'Off The Course'
Complete Ulf Ironbeard's campaign
Complete Rurik's campaign
Complete Edward the Confessor's campaign
Complete Harold II Godwinson's campaign
Complete Rudolf I's campaign
Complete Mieszko I's campaign
Start a match in Multiplayer or Skirmish against any opponent
Win a Multiplayer match or Skirmish in less than 8 minutes
Win a match against an AI on Insane difficulty
Specialize ten squads
Unlock veterancy on any unit ten times
Replenish a squad ten times
Destroy a village with Gold defense
Defeat each type of unit in the game at least once
Recruit each type of unit in the game at least once
Detect and destroy five enemy traps
Send peasants to work at a resource point 50 times
Defeat an entire enemy squad with only ranged attacks
Help at least 8 drakkars survive in the mission 'The Last Impediment'
Capture and hold all the villages in the mission 'Battle on Two Fronts'
Deliver 5+ catapults before night-time in the mission 'Wells Under Siege'
Kill Harald Hardrada in less than 5 minutes in 'Before They Find Out'
Pick up all the armors in the mission 'The Siege Of Vienna'
Capture the village of Kopyto in mission 'The Battle Of Cedynia'
Kill 2000 peasants
Sneak into the enemy base undetected in the mission 'Siege Of Niemcza'
Find out what happened to the villagers in the mission 'Battle Of The River Bug'
Destroy all the enemy ships in the mission 'Fearsome Mercenaries'
Complete Boleslav I the Brave's campaign
Kill every bandit and save all the villagers in 'The Knights Of The Cross'
Defend Lubawa using only ranged units in the mission 'Battle Of Lubawa'
Capture all the villages in the mission 'Battle Of Christburg'
Disarm all the traps without being detected in the mission 'The Night Hunters'
Finish the 'Battle of Lidzbark' in less than 25 minutes
Complete the Teutonic Order campaign
Complete all the campaigns of the Vikings, Anglo-Saxons, Germans and Slavs