long , long ago there lived a man called sentaro . his surname meant " millionaire , " but although he was not so rich as all that , he was still very far removed from being poor . he had inherited a small fortune from his father and lived on this . he spent his time carelessly , without any serious thoughts of work , till he was about thirty - two years of age . one day , without any reason whatsoever , the thought of death and sickness came to him . the idea of falling ill or dying made him very wretched . " i should like to live , " he said to himself , " till i am five or six hundred years old at least , free from all sickness . the ordinary span of a man 's life is very short . " he wondered whether it were possible , by living simply and frugally henceforth , to prolong his life as long as he wished . he knew there were many stories in ancient history of emperors who had lived a thousand years . there was a princess of yamato , who , it was said , lived to the age of five hundred . this was the latest story of a very long life record . sentaro had often heard the tale of the chinese king named shin - no - shiko . he was one of the most able and powerful rulers in chinese history . he built all the large palaces , and also the famous great wall of china . he had everything in the world he could wish for . but in spite of all his happiness and the luxury and the splendor of his court , the wisdom of his councilors and the glory of his reign , he was miserable because he knew that one day he must die and leave it all . when shin - no - shiko went to bed at night , when he rose in the morning , as he went through his day , the thought of death was always with him . he could not get away from it . ah - if only he could find the " elixir of life , " he would be happy . 
he also wanted to live a long time .
why did sentaro think of people who had lived a long time ?
why did sentaro think of people who had lived a long time ?