Originally called Vanderbilt Avenue, one of several local streets named after Gilded Age industrialists (e.g., Carnegie Street). Back then, this community was known as Bairdstown, after the Baird brothers – George, Arthur, Joel, and Llewellyn – who subdivided the land in 1903-1905. In March 1917, two years after Los Angeles annexed Bairdstown, residents got the City to change Vanderbilt Avenue to El Sereno Avenue; soon the post office adopted the El Sereno name and Bairdstown was no more. But it’s unknown who came up with “El Sereno” or why. (One source credits Flora Bailey, whose husband Walter ran the L.A. Military Academy here, but I found no proof.) I suspect it’s a bit of Spanglish: since sereno is Spanish for “serene”, the Anglo residents of 1917 may have thought el sereno translated as “the serene place”. But it doesn’t. It means “the night watchman”. Not unlike the old English town criers who would yell, “Ten o’clock and all’s well!” a Spanish sereno would call out, “¡las diez y sereno!” and that’s how the name came about. Some believe those old Bairdstowners totally had watchmen in mind when they rechristened this place, but I’m skeptical. Anyway, El Sereno Ave. was once a longer thoroughfare, but most of it was renamed Eastern Ave. in 1926.