Before known as Chateau Rossmore and Mauretania, two of Rossmore Avenue’s most iconic apartment buildings were originally called: Si-Mar and Mar-Si. Not confusing at all, right?
Husband-and-wife owners Silas and Margaret Slusher commissioned both edifices within a year of each other, with the French chateau (555 N. Rossmore) opening in April 1934 as Si-Mar, a combination of the first syllables of their names. Seven months later, when construction began on their Streamline Moderne masterpiece, 350 feet away at 520 N. Rossmore, they swapped the order so Margaret took precedence with Mar-Si.
The two projects were brought to life by the same team: architect Milton J. Black and contractor Security Finance and Building Company, led by president Herbert Ketell—who took up residence in the Chateau’s Art Deco penthouse for several years.
For some reason, Jack Haley is widely credited with commissioning the Mauretania (which took its current name around 1950), but the actor does not appear anywhere in the original permits or newspaper articles, only the Slushers.
In fact, the Wizard of Oz star’s first connection to the building wasn’t until 1960, when John F. Kennedy stayed in the penthouse during the Democratic National Convention—and Haley is noted in newspapers as the Mauretania’s current owner. Furthermore, I cannot find a single historical article that mentions any association between Haley and Black.
There is zero evidence that the Mauretania was built for Jack Haley. However, two plaques erected in front of the landmark, one of which was bestowed by the Windsor Square-Hancock Park Historical Society, credit the actor with commissioning Milton J. Black back in 1934.
As it turns out, in early 2024 the larger plaque featuring the illustration of the RMS Mauretania was stolen.
In the 1930s, Rossmore Avenue was dubbed “The Park Avenue of Los Angeles” for its popularity among socialites of the East. In addition to Si-Mar and Mar-Si, other landmarks include the Ravenswood, Country Club Manor, Hermoyne, and El Royale.
