Complex sentence: After a short time, Smith was appointed to the pastorate, an office that seems to have only existed in the British Mission and only for a short time, in which position he presided over the Sheffield as well as four other adjacent conferences.
Split into simpler sentences: After a short time, Smith was appointed to the pastorate, an office that existed only in the British Mission for a short time. In this position, he presided over the Sheffield Conference as well as four other adjacent conferences.