"Pliny the Elder (23-79 AD) wrote about how they [the Romans] used to grow, harvest and cook broccoli."(2) An ancient text told about Emperor Tiberius' jabbing at his son Drusas for having a major appetite for the veggie(1). "It is said that the Romans used to boil broccoli with a mixture of spices, onion, wine and oil (as evidenced in the recipes of the gastronome Apicius)." They also used creamy sauces for broccoli and even ate them raw before banqueting(2).
[More modern-day] broccoli began to spread from Italy in 1533 with the marriage of Catherine (Caterina) de' Medici to Henry II of France, from where it spread to England. The 1724 edition of Miller's Gardener's Dictionary called it "Italian asparagus." It took some time for it to catch on in both countries because of the sulfur smell made while it cooked, but it did(2).
Italian colonists brought broccoli to the US in the early 1700s, where between then and the 1800s, it was featured in different cookbooks. "In 1923 D’Arrigo Bros. Company planted trial field of Italian sprouting broccoli near San Jose, California" and began shipping it packed in ice via railroad to markets out east the next year(1).
References:
1. "History of broccoli." Food History. Food History. 20 Sep. 2014. Web. 1 Mar. 2021. https://www.world-foodhistory.com/2014/09/history-of-broccoli.html.
2. De Innocentis, Ivana. La Cucina Italiana: Authentic Italian Cooking since the 1920s. Edizioni Conde Nast S.P.A. 13 Nov. 2020. Web. 1 Mar. 2021. https://www.lacucinaitaliana.com/trends/healthy-food/history-broccoli-etruscans-today.