The Buyids belong to Daylam, which is a geographical designation in the country of Gilan, located in the south of the Caspian Sea, and it is a national designation for those who lived in this Iqqa '. The Banu Buaih are Persians who were attributed to Daylam, as their stay in the countries of Daylam long. They were called the Buyids after the grandfather of this family, Abu Shu`a Buwayh Bin Fana Khusraw, and they were a poor family that lived in the country of Daylam.