Complex sentence: According to the dominant tradition, Andros demanded the document and it was produced, but during ensuing discussion, the lights were doused, concealing the spiriting of the parchment out a window and thence to the Oak by Captain Joseph Wadsworth, ancestor of Elijah Wadsworth.
Split into simpler sentences: According to the dominant tradition, Andros demanded the document and it was produced, but the lights were suddenly doused during ensuing discussion. The parchment was spirited out a window and thence to the Oak by Captain Joseph Wadsworth, ancestor of Elijah Wadsworth.