The Rev. Robert H. Schuller was in Los Angeles on Thursday for the start of a 10-day trial over claims he and his family have made against the ministry he founded in 1955 in Orange County.
The intellectual property, copyright and contract violation claims stem from the Crystal Cathedral's 2010 bankruptcy filing.
The church owes creditors $12.5 million, but Schuller's claims have delayed those payments.
Crystal Cathedral Ministries chief executive John Charles says they could also jeopardize the future of the church.
The Roman Catholic church bought the ministry's glass-paned cathedral last year, but the congregation will move to a new location by next year.