The Brooklyn Life, a magazine lagely focused on the activities of Brooklyn's upper crust, described where and how many Italians were living in Brooklyn in 1903.  

...New York has more Italian residents than the entire population of either Venice or Florence and half as many as the entire population of Rome. In Brooklyn alone there are some forty thousand.... All told, there are eight distinct colonies in the borough, the largest of which extends east and north from Hamilton Ferry into more than a dozen thoroughfares, including almost all of Columbia street. Here there are eleven thousand sons and daughters of Italy....