some sayyids also claim to be ""najeeb al tarfayn"", meaning "noble on both sides", which indicates that both of their parents are sayyid. but in actuality this term is applied only to those sayyids who have both imam hassan and imam hussain in their ancestry. these sayyids, especially in the arab world, would keep the prefix of "sayyid alshareef" or "shareefayn", or "sayyidayn" or "sheikh assayyid" before their names, followed by their father's and grandfather's names and then the clan's and tribe's names followed by "alhasani bil hussaini" or "al hussaini bil hasani", depending on which imam is patrilineal or matrilineal. many sayyids, especially in south asia and shia sayyids, think that only the progeny of both sayyid parents are called "najeeb al tarfayn", but this idea may be attributed to a lack of knowledge in arabic language and genealogy. the importance of this concept of "najeeb altarfayn" has its source in the hadeeth of muhammad wherein he stated that the mahdi, or "the hidden one", would be "najeeb altarfayn" from his lineage. hence, shia and sunni sayyids have different interpretations of this concept.in the arab world najeeb altarfayn saadah would keep two white-colored daggers as opposed to just one by other sayyids to demarcate their superiority amongst them. hence their international coat of arms also shows two daggers.