Conversation so far:
Did Varg commit any arson?
In 1993, he was convicted of murder and arson, and subsequently served 15 years in prison.
When was Varg Vikernes' first case of arson?
On 6 June 1992, the Fantoft Stave Church, dating from the 12th century and considered architecturally significant, was burned to the ground by arson.

Question: Why did he burn it?
Self-contained rewrite: Why did Varg Vikernes burn the Fantoft Stave Church?