711 CE is the earliest “start date” used by historians for the “Golden Age of the Jews of Spain.” Others place the “start date” at 912 CE (the rule of Abd–ar–Rahman III).
Depending on the historian, this (“Golden Age”) period ends either in 1031 CE (when the Caliphate of Cordoba ended) or 1066 CE (the year of the Grenada massacre) or 1099 CE (when the Almoravides invade) or the mid–1100s CE (when the Almohades invade)
So, at a minimum, 100 years;
at a maximum, almost 450 years.
Now, there is much disagreement as to just how “golden” this “Golden Age” was.
Was it objectively “golden”? or just relatively golden – as compared to Christian Europe?
Probably, the latter.
But, “relatively golden” may have been a quantum–leap significantly better “neighborhood” for a Jew to live in – and bring up his family. That would be my estimation. Furthermore, one needs to assume that the level of “golden–ness” oscillated over the span.
However, one should not underestimate the political capital expended by sundry Muslim rulers extending various levels of protection, tolerance, respect and harmony to the Jews.
Of course, historically there have been extraordinary cultural and economic—and often scientific and political—benefits to shielding “those Jews.” But the Muslim rulers as a general rule clearly acted responsibly and often quite nobly.
Life for a Jew in contiguous Christian Europe spanning the widest demarcation of this period was more often than not a hellish existence. The breadth and depth of Christian toxicity towards the Jews is numbing.
*
Maimonides, oft–cited as the exemplar of a Jew in this (Spanish) Golden Age, was only born in 1135 CE, so his own zenith does not truly catch even the fourth and last possible historical cut–off date (mid–1100s CE) noted above for the era. We include him in Golden Age of Jewish Philosophy (1200s–1400s), but not in the Golden Age of the Jews of Spain. See 1200 CE below.