Complex sentence: They quickly established a firm friendship, with Olivia listening sympathetically to his obsessive love for Maud; as Yeats described their friendship, "I told her of my love sorrow, indeed it was my obsession, never leaving by day or night".
Split into simpler sentences: They quickly established a strong friendship, with Olivia listening sympathetically to his obsessive love for Maud. When Yeats later described their friendship, he wrote, "I told her of my love sorrow, indeed it was my obsession, never leaving by day or night".