Complex sentence: He retired in this year, selling off all his assets over the next three years and retiring to Llanfoist near Abergavenny, where he lived in Llanfoist House.
Split into simpler sentences: He retired in this year, selling off all his assets over the next three years. Before 1851 he had retired to Llanfoist near Abergavenny, where he lived in Llanfoist House.