Complex sentence: The Central Committee of the Purge Board for Artists held an inquest into the matter on 27 January 1946, wherein a handwriting expert determined that the entire inscription had been written at once, and was written by van Meegeren.
Split into simpler sentences: The Central Committee of the Purge Board for Artists held an inquest into the matter on 27 January 1946. While one handwriting expert determined that the entire inscription had been written at once, and was written by van Meegeren.