The accession of King Vajiravudh (Rama VI, reigned 1910–1925) was the least problematic succession in the history of the Royal House of Chakri up to that point. After the premature death of Crown Prince Maha Vajirunhis, his younger half brother, Prince Vajiravudh was invested as crown prince in 1895 and, upon the death of his father King Chulalongkorn, acceded to the throne. Based on his own experience as heir, King Vajiravudh knew that his father had wanted to institute a more ordered system of succession on the basis of primogeniture which unequivocally designated a crown prince. During his reign, he set the precedent for numbering Kings of Thailand as "Rama" by styling himself as "Phra Ram thi Hok" (.) Rama VI, however, was unable to produce a male heir and, as a result, succession became an issue again.