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In the umavid's era there were two kina's of active centers scientific and
literary
1. Centers that were established before the emergence of Islam by some of
the ethnic Greesks, Iranians and syncs, in Egypt, Iran and cities like Nasibein and Raha, mostly dealt with rational and medical sciences. These centers were active for a long time without being dependent on Islamic caliphate reigns and could continue their scientific and research works.
2. Centers that were flourished by the efforts of the moslem nations, tumed into great Islamic science and civilization centers. In these places, rather than Hadith other Islamic and Quranic sciences including (readings and interpretations) were mostly practised, while the other branches of sceinces did not have a place at that time.