First of all, let it be understood that the 'comic' in Sri Lanka, in the Sinhala language, dealt with serious themes, as opposed to, say, American comics which dealt with fantasy, be it Caspar, the Fantastic Four or Batman. The Sinhala comic in its heyday from the 1960s to the 80s dealt mainly with two themes -- love, and adventure, including historical adventure stories.
The above picture shows the front and back covers from an early Sinhala comic by G. S. Fernando. A pioneer of the Sinhala comic, G. S. was a superb illustrator and artist with a fluid, even minimalist style. He is credited with the first ever Sinhala comic to be published as a book -- Neela, which unfortunately I do not have. The book shown here contains nine short illustrated stories, all of which were carried in the popular monthly Rasavahini magazine prior to being published as a book. The stories were written by others. One of them, Dharma Sri Kaldera, went on to become a scrpt writer and film maker.
Unfortunately, the year of publication is not given in the book. I think this one dates back to the sixties.