who trace, or pretend to trace, their descent to the early nobility of Islam:
  Sprenger adduces a curious example in the Moslems of Paniput. These are
  composed of four castes: the descendants of Abu Ayûb (the citizen
  whose guest the Prophet was on his first arrival at Medina); the descendants
  of Othmân; Affghans; and converted Rajpoots. The first two do not
  intermarry with the two last. They carefully maintain their genealogical
  trees, in which the pedigree is followed up step by step to the founders of
  the family in the very age of Mahomet; in later days the births and deaths are
  entered, and sometimes the marriages also, with the dates. The pedigree of the
  Qthmânite clan is carefully kept in the custody of the Nawab, the head
  of the house, but Sprenger does not think it really above a hundred years old.
  For the last seventeen or eighteen generations, that is, up to the time of
  Alauddeen Shah, when the family first entered India, the details may be
  founded more or less on fact. Beyond that, the descent runs through kings of
  Herat, Sheraz, Kafaristan, Balkh, etc., and is pure fabrication. The same is
  the experience of Sprenger with all the other pedigrees he has met in India.
  "Life in the East," he says, "is all too insecure, and under
  too arbitrary a government, to look for archives extending over several
  centuries. In the deserts of Arabia such documents are altogether unknown; and
  it would be childish to imagine that the minute ramifications of any tribe
  could be retained in the mere memory for a long series of years." 1