Question: What was the origin of Udon that took place in 1241?
About the article "Udon", section "Origin".

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Udon Thani means Northern City.
The origin of the name "Udon Thani" is lost in history. 
There are many stories explaining the origin of udon.
One story says that in AD.1241, Enni, a Rinzai monk, introduced flour milling technology to Japan.
Floured crops were then made into noodles such as udon, soba, and pancakes which were eaten by locals.
Milling techniques were spread around the country.
In the Edo period, the thicker wheat noodle was generally called udon, and served with a hot broth called nurumugi(温麦).
The chilled variety was called hiyamugi(冷麦).
Another story states that in Nara period, a Japanese envoy was introduced to 14 kinds of confection whilst in Tang Dynasty China.
One of them was called sakubei(索餅).
Sakubei was listed as 'muginawa'(牟義縄) on Shin Senji Kyo(新撰字鏡), a dictionary which was published in Heian Era.
The muginawa is believed to be an origin for many kinds of Japanese noodles.
However, the muginawa listed on Shin Senji Kyo(新撰字鏡) was made with wheat and rice flour.
Another historical story for udon claims that the original name of the noodle was 'konton', which was made with wheat flour and sweet fillings.
Yet another story says that a Buddhist priest called Kukai introduced udon noodles to Shikoku during the Heian Era.
In China, similar thick wheat flour noodles are called "cū miàn" (粗麵).
This noodle was 2 to 3 mm in diameter, a flat pancake-shaped "noodle" added to miso-based soup.
The Sino-Japanese characters for udon (饂飩) is similar to, but different from, the modern Chinese characters for wonton, which is called hún dùn in Mandarin (馄炖), a type of dumplings.
In Chinese, udon noodles are called "wūdōngmiàn" (烏冬 "wūdōng" or 烏冬麵), and sometimes "wūlóngmiàn" (烏龍麵), which has the same characters as those used in "Oolong" tea ("wūlóngchá", 烏龍茶), though there is no semantic relation between the two usages.Kūkai, the Buddhist priest, traveled to China around the beginning of the 9th century to study.
Sanuki Province claimed to have been the first to adopt udon noodles from Kūkai.
Hakata claimed to have produced udon noodles based on Enni's recipe.
The founding priest of the temple, Enni-Ben'en went to China in 1235, mastered Zen Buddhism through a great hardship and came back to Japan in 1241.
He brought home to Japan a variety of cultures from China besides the teachings of Buddhism.
The production method of Udon, Soba, Yokan and Manjū are especially famous among them. 
  "Kake udon" (in Kantō) or "Su udon" (in Kansai): Hot udon in broth topped with thinly sliced green onions, and perhaps a slice of kamaboko.
"Kitsune udon": "Fox udon".
Topped with aburaage (sweetened deep-fried tofu pockets).
"Tempura udon": Topped with tempura, especially prawn, or "kakiage", a type of mixed tempura fritter.
"Tanuki udon" ("Raccoon-dog udon") (in Kantō) or "Haikara udon" (in Kansai): Topped with tempura batter pieces.
"Tsukimi udon": "Moon-viewing udon".
Topped with raw egg, which poaches in the hot soup.
"Wakame udon": Topped with wakame, a dark green sea vegetable.
"Karē udon": "Curry udon".
Udon in a curry-flavoured soup which may also include meat or vegetables.
Biei, Hokkaido is famous for a unique curry udon.
"Chikara udon": "Power udon".
Topped with toasted mochi rice cakes.
"Stamina (sutamina) udon": "Stamina udon".
Udon with various hearty ingredients, usually including meat, a raw egg, and vegetables.
"Nabeyaki udon": A sort of udon hot-pot, with seafood and vegetables cooked in a "nabe", or metal pot.
The most common ingredients are tempura shrimp with mushrooms and an egg cracked on top.
"Kamaage udon": Served in a communal hot-pot with hot water, and accompanied by a hot dipping sauce of dashi and soy sauce.
"Udon-suki": Udon cooked in the manner of sukiyaki.
"Yaki udon": Stir-fried udon in soy-based sauce, prepared in a similar manner to yakisoba.
This originated in Kitakyushu of Fukuoka Prefecture.
(Note that while "yakiudon" is made with udon, "yakisoba" is not made from buckwheat soba, but with steamed Chinese-style ramen.)
"Miso-nikomi udon": hard udon simmered in red miso soup.
The soup generally contains chicken, a floating cracked raw egg that is stirred in by the eater, kamaboko, vegetables and tubers.
The noodles are extremely firm in order to stand up to the prolonged simmering in the soup; additionally, the noodles do not contain salt, so as to avoid over-salting from the salt in the miso.
"Hōtō udon": a local dish of Yamanashi Prefecture, a type of miso soup with udon and vegetables.  
Originally named Ban Mak Khaeng (บ้านหมากแข้ง), the district was one of the original four districts of Udon Thani established during the "thesaphiban" administrative reforms in 1908.
In 1938 it was renamed from Mak Khaeng to Mueang Udon Thani.