Croatia was elevated to the status of kingdom somewhere around 925. Tomislav was the first Croatian ruler whom the papal chancellery honoured with the title "king". It is generally said that Tomislav was crowned in 925, however, this is not certain. It is not known when or by whom he was crowned, or, indeed, if he was crowned at all. Tomislav is mentioned as a king in two preserved documents published in the Historia Salonitana. First in a note preceding the text of the conclusions of the Council of Split in 925, where it is written that Tomislav is the "king" ruling "in the province of the Croats and in the Dalmatian regions" ("in prouintia Croatorum et Dalmatiarum finibus Tamisclao rege"), while in the 12th canon of the Council conclusions the ruler of the Croats is called "king" ("rex et proceres Chroatorum"). In a letter sent by Pope John X, Tomislav is named "King of the Croats" ("Tamisclao, regi Crouatorum"). The Chronicle of the Priest of Duklja titled Tomislav as a king and specified his rule at 13 years. Although there are no inscriptions of Tomislav to confirm the title, later inscriptions and charters confirm that his 10th century successors called themselves "kings". Under his rule, Croatia became one of the most powerful kingdoms in the Balkans.