The Alhambra (Red Castle in Arabic), is a massive (and magical) palace that graces the skyline of Granada in the Andalusian region of Spain. It's hard to believe, but The Alhambra started as a teeny-tiny fortress built on top of Roman ruins way back in 889. Given that it's (at least) 1,130 years old, it's not hard to see why it's one of Spain's most visited sites. To really understand the significance of what is widely considered to be the crown jewel of the Nasrid Dynasty, we need to backtrack.
Let's start in the year 711 when the Moors first made their way into Spain. An army led by Tariq ibn-Ziyad invaded Andalus (Visigoth Spain) via the Strait of Gibraltar and announced that Spain was going to be Muslim and come Hell or high water, they were gonna like it. What came next was a nonstop will-they-won't-they conquer until 732 when the Moors had managed to invade all the way to France where the Francs defeated them at the Battle of Tours and the Asturians in Northwest Spain at the battle of Cavedana.
At this point, all of Visigoth Spain, aside from the newly formed Christian Kingdom of Asturias, became Al-Andalus also known as the Caliphate of Cordoba and Islamic Iberia. It was one Hell of a time to be a Moor in Spain. For the next several hundred years, the Moors continued to prosper, and Al-Andalus slowly evolved into one of THE spots to be for academics with constant advances in trigonometry, astronomy and even surgery.
It widely debated today on what it was like to be a Christian, Jew, or Pagan during this time. It's known that non-Muslim men were subject to a tax called "Jizya" and that there were "intermittent bouts" of persecution against Dhimmis, though it was rare. It's also known that non-Muslims were considered second-class citizens but didn't wind up in a massive ethnic purge like most conquests during that time. For the most part, the Moors were tolerant, and it only helped their cause as Al-Andalus continued to grow into a cultural hub of Europe.
Side note: Dhimmi translates to "protected person" in Arabic. A Dhimmi is a non-Muslim person living in an Islamic State with legal protection to practice their religion, own property, exercise freedoms, etc. as long as they pay a tax.
Fast forward to the mid 13th century when Nasrid Emir Mohammed Ben Al-Ahmar decided to pull a full-on Fixer Upper and renovate the Alhambra into most of what we know today.