Complex sentence: Soane hoped that one or both of his sons would also become architects, and Pizhanger was to be inducment to this end, but both sons became increasingly wayward in their attitude and behaviour, showing not the slightest interest in architecture.
Split into simpler sentences: Soane hoped that one or both of his sons would also become architects. But both sons became increasingly wayward in their attitude and behaviour, showing not the slightest interest in architecture.