この物語の福の神のモデルは、明治時代に、仙台市に実在した人物です。
説話にはいろいろあるようですが、
取りたてて、何か大きな仕事をした訳ではなく、その人の肖像画が、家運上昇、商売繁盛に御利益があるとして、飛ぶように売れ、その人形さえ作られています。
そもそも四郎さんは、少々知的障害を持った人物だったようですが、
元々は聡明な子供だったが、7歳の時に花火見物中、誤って広瀬川に転落して溺れ、1週間意識不明で生死の境をさまよったのが元で、知能の発達が遅れだしたという。最初は、何となく、人のうちに来ては、愛想の良い笑顔を振り撒いて、帰っていく、ただそれだけの人物と思われていた。…ところが、である。不思議なことに四郎さんがやって来た家は、運が次第に向いてきて、良いことばかり起こる。やがてそのことが町中の評判となったらしい。
ある話では、ある時事業がうまく行かず、死ぬことさえ覚悟した人物の家の前に、ふらっと現れた四郎さんはこう言いったという。「そんな恐い顔しないで、俺みたいに笑ってけさいん」（仙台弁で笑ってください）四郎さんに、そう言われて、ふと鏡で自分の顔を覗いて見ると、そこには鬼のような形相になっていた自分がいたのでした。これでは他人相手の商売もないと、はっとして目が覚めたそうです。
それからは幸運が押し寄せてきたとのことです。引用http://www.st.rim.or.jp/~success/senndai_sirou_ye.html

また、ある説話では

仙台四郎（せんだいしろう、1860年頃 - 1902年頃）は、明治時代の仙台の人で、現代まで福の神として崇められている。本名は芳賀四郎。知能障害で話すことができなかったが、四郎がいる店は繁盛するとして各地でもてなされた。没後、商売繁盛のご利益があるとしてその写真が飾られるようになり、今日に至るとあります。
人物的には、言葉は「バアヤン」としか話さず、市中を歩き回って人に金品をもらったりしていた。人に危害をなすことはなく、子供が好きで、いつもニコニコと機嫌よく笑っていたという。立ち寄る店は必ず繁盛するとされたため、どこでも無料でもてなされた。四郎は素直な性質であったが、気に入らない店には誘われても決して行かなかったという。やはり無料で鉄道を利用し、白石、白河、福島、山形まで足を伸ばしていたらしい。1902年頃に47才で須賀川で死んだとされるが、はっきりしない。なお記録としては鉄道で外遊に出る由、新聞記事に載ったものが最後と云う。

引用出典: フリー百科事典『ウィキペディア（Wikipedia）』より
The model of the God of Wealth of this tale is the person who exists in Sendai City in Meiji era.
But variously in the story
It sells to splash and even the doll is made if collecting and not doing any big work and the portraiture of the person supposes that the divine favor is in the fortunes of a family rise, the business prosperity.
But in the first place, Shiro seems to have been the person who has a little intellectual disabilities
Originally, it was an intelligent child but it says that it fell to Hirose-gawa by mistake during firework sightseeing at the time of 7 years old and that it drowned, that it is original that wandered the border of fate, that 1 week was unconscious and that it began to be behind in the development of the intelligence.
At first, as for coming somehow into the person, it strewed an amiable good smiling face and it seemed the person only of it which returns.
...However, it is.
As for the house where Shiro came to the mysterious thing, the luck turns gradually and only the good thing happens.
The thing seems to have become reputation in the downtown finally.
Shiro who appeared without any definite purpose in front of the house of the person who awoke even to that some current industry didn't go in some story, being good and dying says that the word went thus.
【翻訳不能文】
Under present condition, when there is not a stranger partner business, too, it is startled and it seems that it wants to wake.
Luck is since then said to have surged.
Quotation http://www.st.rim.or.jp/~success/senndai_sirou_ye.html
By also some story
Sendai
Shiro ( being んだいし wax, a 1860 marriageability -1902 marriageability ) is a person in Sendai in Meiji era and is honored as the God of Wealth until today.
Honna is Haga Shiro.
It wasn't possible to speak by the intelligence impairment but it was entertained with each place if supposing that the shop where there is Shiro was prosperous.
The photograph becomes decorated if supposing that there are after the death, divine favor of the business prosperity and there is と to today.
Like a person, the word talked only with " バアヤン " and was getting money and valuables from the person by strolling in the city.
It never accomplishes harm, it likes the child and he says to have always been laughing with a pleasant smile and mood well to the person.
Because a calling shop was supposed to be always prosperous, it was for free entertained anywhere.
Shiro was obedient nature but says that it was decided and that it didn't go even if it was invited to the shop which doesn't like it.
It uses a railroad still for free and it seems that it is stretching a leg to Shiroishi, Shirakawa, Fukushima, Yamagata.
It is supposed to have died in Sukagawa at 47 years old to 1902 marriageabilities but it isn't cleared.
Incidentally, as the record, the one which is in the circumstances, the newspaper article to be over says to the overseas travel that it does the last by train.
The quotation source: From free encyclopedia " ウィキペディア (Wikipedia) "