I have been watching some BBC documentaries on the history of Spain recently. 'Blood and Gold: The Making of Spain with Simon Sebag Montefiore', and 'The Art of Spain' (Episode 1: The Moorish South).
These documentaries examine Al-Andalus, and particular attention is given to what seems like a remarkably tolerant and enlightened era during the Caliphate. This contrasts sharply with the intolerance of subsequent regimes. After 1147 the Muslim Almohads from the Maghreb forced Jews and Christians to convert, and later Christian rulers offered the country's Jews the choice of conversion or expulsion with the Alhambra decree of 1492.
What I'd like to understand is why exactly was the Caliphate so exceptional in its tolerance of Christians and Jews, and its patronage of science and art? What factors influenced this behaviour that made this period so different from anything which followed?
EDIT: To quote Mark C. Wallace in the comments:
'Why the phenomena existed. Seems to me there are two subordinate questions: (1) was this era tolerant (or cosmopolitan)? Was violence diminished? What about non-violent conflict? (2) To the extent that the era was tolerant (however defined), why?'
This relates to the academic debate over 'La Convivencia'. It however seems that this era is defined too broadly, leading to confusion. For example, the 1066 Granada Massacre occurred decades after the Emirate/Caliphate had collapsed in a civil war (1009-1031). It should therefore be unsurprising that there was less tolerance and more violence after the Caliphate and thus rule of law failed.
An answer must explain if and why cosmopolitan society existed during the Emirate/Caliphate of Cordoba (756-1009). We define cosmopolitan society here in terms of relative tolerance amongst Muslims, Christians, and Jews, as well as the patronage of science and the arts.
I expect this will be able to be answered by someone with broad knowledge of Islamic civilisation, and thus someone who can make a comparative analysis of the factors involved.