Signboard Shiab Bani Hashim
Amongst pre-Islamic Arabs people classified themselves according to their Confederation, their tribe, their clan, and then their house/family. There were two Tribal Confederations; the Adnani (originating from "Adnan", the traditional ancestor of the Arabs of northern, central and western Arabia), and the Qahtani (originating from "Qahtan", the traditional ancestor of the Arabs of southern and south eastern Arabia). Banu Hashim is one of the clans of the Quraysh tribe, of the Adnani confederation. It derives its name from Hashim, the great-grandfather of Muhammad, and along with the Banu Abd Shams, Banu Al-Muttalib, and Banu Nawfal clans comprises the Banu Abd al-Manafsection of the Quraysh.
The house of 'Abd al-Muttalib of Banu Hashim of Quraysh comprised a form of nobility in pre-Islamic Makkah, based upon their hereditary duty to act as stewards and caretakers of the pilgrims coming to Makkah to worship at the Kaabah. This was the sacred shrine in that city, which in Islamic tradition was built by the prophet Ibrahim(Abraham) and his first-born son and heir Ismail (Ishmael), which had come to be occupied by some hundreds of idols. The idols represented many different tribes and as a result Makkah became a centre of pilgrimage, and the Kaabah's environs were an inviolable sanctuary. This pilgrimage traffic added considerably to the wealth of the merchants of Makkah, which also benefited from its position astride the caravan routes from Yemen (Arabia Felix) up to the Mediterranean markets.
It was into the house 'Abd al-Muttalib of Banu Hashim of Quraysh that Muhammad was born in the year 570 C.E. From 610 C.E. his mission to call people to the worship of the One God set him at odds with the established powers in Makkah. His membership of the 'top house, of the top clan' (in terms of prestige, though not power) was a factor in keeping him safe from assassination during the early years of his mission, as a number of his uncles would not countenance any such insult to their clan honour.
In the year 622 C.E. the Muslim community of Makkah made Hijrah/emigrated to the city of Yathrib, which subsequently became known as Madinah, to avoid the often murderous persecution of the pagans of Makkah.
With the conquest of Mecca in 630, the city was captured by the army of Islam. The Kaabah was cleansed of idols and became the centre of pilgrimage for Muslims. (It is forbidden to non-Muslims to enter an area designated around the city of Makkah).
Though Muhammad had a number of wives few of his children lived long enough to produce any ongoing lines of descent. The two major lines of descent are those of his two grandsons, Al-Hasan and Al-Husayn, born of the union of his daughter Fatimah and his cousin/son-in-law Ali. Muhammad besought the mercy of the Muslims upon his beloved grandsons, thus their descendants have become a form of spiritual aristocracy amongst many, though not all, Muslims. The descendants of Muhammad's grandsons are known by the titles of Sayed (Sayyid, Syed, etc.), or Sharif/Sherif.
It is to be noted though that over the centuries a great many 'false' Sayedi/Sharifi lines of descent have developed. These have often arisen not through deceit upon their part as much as through the obfuscation of genealogical identity over largely unrecorded centuries. Two known clusters of 'false Sayeds' are: the so-called 'Sayeds of Sindh' in modern Pakistan, descendants of the Ansar (helpers) of a Sayedi/Sharifi refugee from Madinah whose line died out early on thus creating the impression amongst the descendants of those who sheltered him that they were Ahl an'Naas ('of the blood') and the 'Talukdari Sayeds' of Hyderabad Deccan in Southern India, the descendants of Muhammad an adopted son of Muhammad and therefore also not 'of the blood'.
There are also many Hassani and Hussayni (double s lines) who claim to be descendants of the Prophet but who are not so in reality, this is a long attested fact; as well as which there are those who falsely claim descendants of the Prophet Muhammad's uncle Al-Abbas to constitute part of the Ahl an'Naas (House of the Blood) of the Prophet, the which is mostly done by Abbasis who wish to appear as descendants of the Prophet, 'though these are possible descendants of the Abbasid line which is separate to Banu Hashim; along with many of the Shia'at Ali who claim that descent through Ali is as, if not more, significant in terms of descent from Muhammad and thus falsely try to include Alvis and a cluster of others under the umbrella of being descendants of the Prophet Muhammad despite the clear lack of any blood lineage.