7 Wives of 7 Wise Men

The 7 wives of the Sapta Rishi were originally the 7 Krittika sisters. Svaha disguised herself as 6 of the Krittika sisters and had a relation with Agni which resulted in the birth of Kartikkeya. The 6 Kartika sisters became the Pleiades. Only Arundhati as Alcor remained faithful to Vasistha.