History of Almonds
Wild almonds are related to peaches and apples, and probably evolved about the same time, around five million years ago. Like peach trees and apple trees, almond trees made cyanide poison to keep sheep and goats and rabbits from eating their fruit.
Peach trees grew in East Asia (China), and apple trees grew in Central Asia, but almond trees grew in West Asia. People ate the fruit of peaches and apples, but they didn't eat almonds - both the fruit and the nuts tasted bitter with cyanide, and if you ate even a few dozen at the same meal the poison might kill you.
So easier plants like figs and apples were farmed first. But by 3000 BC, farmers along the Eastern Mediterranean coast (modern Israel and Lebanon) figured out how to select the few almond trees that didn't make this poison - sweet almonds - and plant those. You still couldn't eat the fruit, but you could eat the pits - the nuts. Almonds were easy to grow and pick and you don't have to cook them, and they had a lot of fat and protein, so they quickly became very popular all across West Asia, as far east as Persia and Sogdiana (modern Pakistan and Afghanistan).
Almond harvest near Tashkent under
Hamida Banu (1590s AD, Qand-i Badam)
When the Egyptians conquered Israel and Lebanon about 1400 BC, traders began to sell almonds to people in Egypt. When the Phoenicians invaded and founded colonies in North Africa about 800 BC, they brought almonds with them and planted almond orchards there. Soon after that, farmers were growing almonds in Greece, and then when the Romans conquered Greece in the 100s BC they brought almonds back to Rome. Soon people were growing almonds all over the Roman Empire, in Spain and southern France and Italy.
Almonds travelled east with the Mughal invasions of India, and by 1700 AD farmers were growing almonds all over India. Not long after that, almonds finally came to Ch'ing Dynasty China (earlier references to Chinese almonds are really about apricot pits).
When Spanish Franciscan monks invaded California in the 1700s AD, they brought almonds with them, too. The almond trees didn't grow well along the coast, but by the 1800s California farmers had found a home for almonds further from the ocean, where it was dryer. Today most US almonds come from California, and California also ships lots of almonds to India and China, where almonds have become very popular.
Bibliography and further reading about almonds: