Complex sentence: The second edition of novel (1911) states that Padmanabhapuram was earlier the capital of Tiruvitāṁkōṭŭ state; which, according to Dr. P. Venugopalan is a slip up happened in revising the first edition (1891) of the novel.
Split into simpler sentences: The second edition of novel (1911) states that Padmanabhapuram was earlier the capital of Thiruvithamkodu state. According to Dr. P. Venugopalan this is a slip up happened in revising the first edition (1891) of the novel.