Before 1900, a Japanese wedding was ordinarily a domestic event held in the home, without a fixed shrine liturgy attached to it, and Shinto shrines played no standard role in how a marriage was solemnized. The shrine wedding as it exists today was devised for a specific, highly public occasion: the 1900 marriage of Crown Prince Yoshihito, the future Emperor Taisho, which was conducted at the Hie Shrine in Tokyo with a ceremony constructed for the purpose, drawing consciously on the form of a Christian church wedding while filling it with Shinto liturgical content.
Following the imperial wedding, Shinto shrine associations promoted the same format to the wider public as a model of a properly Japanese and properly religious wedding, distinct from both the older domestic custom and from the Christian style weddings that a minority of Japanese Christians were already holding. The new form spread quickly through the early twentieth century and by the postwar period had become the default understanding of what a traditional Japanese wedding looked like, despite being, in the form practiced, barely older than the twentieth century itself.
Today Shinto weddings compete with Christian style ceremonies, held in wedding chapels without reference to any actual church, and with entirely secular civil ceremonies, and shinzen kekkon is now a minority choice among Japanese couples rather than the default it briefly was.