Why didn't he succeed to the throne later on?
那么，他后来为什么不继承王位呢？

Prince Siddhattha in his childhood developed the habit of meditating. Many phenomena he observed touched him strongly and made him think hard: e.g. the hungry, thirsty and exhausted peasants working under the scorching sun, panting and sweating cattle being flogged as they plough, the struggle among snakes, insects, birds and beasts under the law of the jungle, weak and ugly old people, the moaning and suffering sick, the dead in funeral processions with their families and friends weeping behind. All these presented him with a problem: how to deliver the world from suffering. Neither the Veda he had read nor the knowledge he had acquired, nor his future throne and power could solve this problem. Therefore, he harbored the idea of renouncing the world in his early days, and finally he relinquished his throne.
悉达多王子在幼年的时候，就有沉思的习惯，世间许多现象，给他看到，都容易引起他的感触和深思：饥渴困乏、在烈日下耕田的农人，绳索鞭打、口喘汗流拖着犁头耕地的牛，蛇虫鸟兽弱肉强食的情景，衰丑龙钟的老人，辗转呻吟的病人，亲朋哭泣送葬中的死人，这些都促使他思索着一个问题——如何解脱世界的苦痛。他读过的吠陀书（Veda，婆罗门经典）不能解决他的问题。他学到的知识和他未来的王位、权力也都不能解决他的问题。于是他很早就有了出家的念头，后来终于舍弃了王位。