The Mononobe clan (物部氏)
It is said that the Mononobe clan's ancestor is Nigihayahimikoto, who is believed to have descended to earth in Koho, Kawachi Province (presumably, present-day Katano City, Osaka Prefecture) before the time of the Imperial family. Originally, the clan administered the manufacturing and maintenance of weapons and gradually became a powerful military clan alongside the Otomo clan. In the fifth century, the Mononobe clan showed great military performance in the conflict over succession of imperial throne and produced the chief administrator in the era of the Emperor Yuraku.
Their Kabane (hereditary title) was formerly Muraji, but the clan was given the kabane of Ason (the second highest of the eight hereditary titles) after the reform of the Kabane system (Yakusa no Kabane). It is well known that there are many clans that have same lineage, such as the Hozumi clan and the Uneme clan.
The Iwai War
When the Iwai War occurred in the northern Kyushu area during the era of the Emperor Keitai, it was the Mononobe clan which was ordered to suppress the revolt. MONONOBE no Arakahi, who quelled the war, died in July in the first year of the Emperor Senka.
According to "Nihonshoki" (Chronicles of Japan), a Buddha statue was sent from Kudara (Baekje) during the era of Emperor Kinmei. The pro-Buddhist faction led by SOGA no Iname and the anti-Buddhist faction led by MONONOBE no Okoshi and NAKATOMI no Kamako struggled over how to treat this statue. However, due to the recent discovery of the remains of former Shibukawa-ji Temple, which was an Uji-dera Temple (temple built for praying for clan's glory) from the Mononobe clan's place of dwelling, it became difficult to categorize the clan as simply anti-Buddhist, and some say that it was a confrontation not over the matters of each clan's reverence, but over religious services over a national scale.
Moriya attacked the Soga clan's temple and threw the statue into the river, then set the temple on fire. Then he lashed three nuns.
After that, a plague spread and Emperor Yomei passed away. This helped the Soga clan which was gaining strong support from the Empress and the Prince and, following the decree made by the Emperor while still alive asking to respect Buddhism, the Soga clan and the allied forces attacked Moriya as ordered by the Empress of the former Emperor Bidatsu (the older sister of the Emperor Yomei and later the Empress Suiko).
At first, Moriya MONONOBE gained the upper hand but he died in his base in Shibukawa County, Kawachi Province (present-day Kizuri, Higashi-Osaka City, Osaka Prefecture).
The Isonokami clan
Known as the Mononobe clan up until 686, from then on the name changed as the Isonokami clan gained the position as head family. The Isonokami clan called itself a descendant of the older brother of Moriya.
ISONOKAMI no Maro, who called himself a descendant of MONONOBE no Me (who was Omuraji in the era of the Emperor Yuryaku), was given the kabane of Ason and was promoted to Sadaijin (Minister of the Left) in 708. When he died, the Emperor mourned over the death and he posthumously received Juichii (Junior First Rank). His son, ISONOKAMI no Otomaro was promoted to Chunagon (vice-councilor of state) in the era of the Emperor Koken and the son of Otomaro, ISONOKAMI no Yakatsugu was promoted to Dainagon (chief councilor of state) in the era of the Emperor Kanmu. Yakatsugu goes down in history as the founder of the Untei (the first public library in Japan).
The Isonokami clan declined in the early ninth century after the death of Yakatsugu.
The Mononobe clan in the provinces
A characteristic of the Mononobe clan was its distribution throughout the country, and including Mononobes which are not given Kabane, they are too numerous to count.
Aside from those Mononobe clan living in the capital like the Isonokami clan, a historical record is left that a person calling himself Mononobe was appointed to the regional officer in Tohoku region of ancient times. According to "Mononobe Bunsho," one of the so-called 'Koshi Koden' (Ancient History and Legends), the Dewa-Mononobe clan called itself a descendant of MONONOBE no Moriya, and Fuso Ryakki (A Brief History of Japan) and Mutsu Waki (A Tale of Mutsu) say that MONONOBE no Nagayori was appointed to Mutsu no Daisakan (the fourth rank officer). However, no evidence of whether the Dewamononobe clan is a real descendant of Moriya can be found. Among the examples of shisei (conferring a surname) to barbarians found in Rikkokushi (the Six National Histories), there is a record that the Kimiko clan was given the Muraji of Mononobe no Shiwa.
In a tradition handed down from the ancestors of Mononobe no Sosa Muraji based in Sosa County, Shimousa Province, there is also a record that MONONOBE no Ogoto, who was a child of MONONOBE no Futsukuru and a younger brother of MONONOBE no Itabi, entered into the Kanto region. There is a theory regarding this that points to a connection with Shita County, Hitachi Province, and also a connection between Katori-jingu Shrine and the Mononobe clan.
A settlement of the Mononobe clan was located in the eastern part of Owari Province of ancient times, and Takamu-Jinja Shrine, which is said to have been an arsenal, and Mononobe-jinja Shrine still remain today. There is also a theory that 'Mononobe-jinja Shrine' (Oda City, Shimane Prefecture), which is an ichinomiya (a shrine occupying the highest rank among the shrines of a province) of Iwami Province was built as an appeasement for ancient Izumo except for the theory of arm control. The Kaneko family, which was a shake (family of Shinto priests serving a shrine on a hereditary basis), was called Iwami no Kuninomiyatsuko and considered as the chief of the Mononobe clan in this region. Before the war, the family held the peerage of Danshaku (baron).
It is said that the Koto clan, the military governor of Nagato and Kaneko clan, the family of Shinto priest of Mononobe-jinja Shrine, and Sone clan, the family of Shinto priest of Hirose-jinja Shrine and Sorai OGYU, shogun's retainer in the Edo bakufu (Japanese feudal government headed by a shogun) are the descendents.