Complex sentence: Coinciding with A.B Wilson's retirement came the Great Depression which limited practicing opportunities, however R.M Wilson succeeded to maintain the firms business by acquiring commison for Gatton's School of Art and Hill End Presbyterian Church Hall.
Split into simpler sentences: Coinciding with A.B. Wilson's retirement came the Great Depression which limited practicing opportunities. However, R.M. Wilson succeeded to maintain the firm's business by acquiring commission for Gatton's School of Art and Hill End Presbyterian Church Hall.