Complex sentence: On 6 September 1678, Oates and Tonge had approached an Anglican magistrate, Sir Edmund Berry Godfrey and had sworn an affidavit before him detailing their accusations.
Split into simpler sentences: On 6 September 1678, Oates and Tonge approached an Anglican magistrate, Sir Edmund Berry Godfrey. In September, Oates and Tonge had sworn an affidavit in front of Godfrey detailing their accusations.