Original: At first comfortably off, he divided his time between Paris and country homes in Villers-sur-Mer and the Cote d’Azur, but after the onset of World War I his circumstances were progressively reduced, he was forced to sell one of his houses and, from 1915, took work lecturing and teaching.
Simplified: At first he was comfortably off, but after World War I the family lost a lot of money and they had to sell their country house.