Here are some facts about the trial:

The actors

– The judges: Breivik's fate will be decided by a panel of five judges, comprising two professional judges and three lay judges whose votes will all weigh equally. The chief judge is one of the professionals, Wenche Elizabeth Arntzen

– The defence: Breivik will be defended by Geir Lippestad and three assistants

– The prosecution: two state prosecutors, Inga Bejer Engh and Svein Holden

– The victims: more than 770 survivors and families of the victims, represented by 162 lawyers

– The witnesses: close to 150 people are expected to testify

Preliminary timeline of the trial

– April 16-23: Breivik testifies

– April 24-30: Focus on the bombing of the government offices, testimony from forensic experts and witnesses

– May 3-June 1: Focus on the shooting rampage on Utøya island, testimony from forensic experts and witnesses

– June 4: Focus on Breivik's arrest

– June 4 and 5: Testimony from Breivik's friends and family  

– June 6: Details from the investigation

– June 7-15: Witnesses called by the defence and counsel for the victims  

– June 18-20: Court-appointed psychiatrists present their diagnosis on Breivik's mental state

– June 21-22: Closing arguments

Sentencing

If the judges find Breivik sane, he risks:

– up to 21 years in prison, the maximum under Norwegian law for "acts of terror"

– preventive detention, which means up to 21 years in prison, with a provision allowing for extensions until he is no longer deemed a danger to society.

If the judges find Breivik insane:

– he will be sentenced to a closed psychiatric ward, possibly for the rest of his life. If he were to be found cured by the care he receives, he could be released as long as he is no longer considered a threat to society. If this condition is not fulfilled, he could be transferred to a prison under a provision that has only been used once in Norway.

The verdict

The verdict is expected in mid-July, though no specific date has been set yet. A majority vote by three of the five judges is needed, and will focus on the question of whether Breivik was criminally sane, which will determine whether he is sentenced to prison or a closed psychiatric ward.