Unjo meikan (the books giving a detailed view of the Imperial family and its offshoots) state that 'the founder was Suketada, Shosanmi (Senior Third Rank) Councilor, who was the youngest son of Mitsuhiro, Shonii (Senior Second Rank) Gondainagon (Junior Chief of the Councilor of State) and six generations away from Toyomitsu KARASUMARU.'
雲上明鑑に、「始祖は烏丸豊光六代正二位権大納言光広の末男正三位参議資忠なり」とある。