Pugu Yitu is not mentioned in the Tang histories, although his grandfather Gelan Bayan is. The Pugu clan was part of the Xueyantuo, a Turkic people who filled the power vacuum in northern Mongolia after the Eastern Turkic Khaganate was defeated by the Tang Dynasty in May 630. In 647 the Pugu clan accepted the suzerainty of the Tang dynasty under the Jimi (loose rein) system and received the title Dudu (Commander-in-Chief). The first Dudu was Pugu Yitu's grandfather Gelan Bayan (歌滥拔延), followed by Pugu Yitu's father Sifu (思匍) who governed till 657. Judging from the epitaph Pugu Yitu was 44 years old when he died in 678. This means he was 22 or 23 years old when he succeeded his father Sifu in the post of Dudu in 657. The inscription was laid flat on the ground in front of the brick-faced main chamber where a number of painted statuettes were found. The main chamber was accessed by three arched passageways. Byzantine-style gold coins were also found. According to the inscription, in the second year of Linde (665) he participated with the Tang Emperor Gaozong in a ceremony on Mount Tai in Shandong Province. The inscription also says he carried out military campaigns against the Mohe in Eastern Manchuria as well as Tibetan Empire (吐蕃). It is notable that General Tonyukuk's Bain Tsokto inscriptions, dated 716, are found eastward in the valley of the same Tuul River in Nalaikh District of Ulaanbaatar. In it he states how Tang influence was still strong in his childhood and how it took him many struggles, including campaigns as far afield as Shandong Province, Tibet and Central Asia to overthrow Tang influence and restore the Turkic Khaganate.