Tadayuki HIROHATA, the third son of Imperial Prince Hachijonomiya Toshihito who was the sixth son of Imperial Prince Sanehito (the Retired Emperor Yoko), and also an imperial descendant of Emperor Ogimachi in the early Edo period, was given the hereditary title of Minamoto and established the family in 1664 by using the surname of Hirohata.
江戸時代前期正親町天皇の皇孫で、陽光院太上天皇誠仁親王の第6王子八条宮智仁親王の三男広幡忠幸が寛文4年（1664年）に源氏の姓を賜り一家を創立し、広幡を称したことに始まる。