It didn't, at least not in 17th-century Rome. The little lighting available was provided by the madonnelle, small shrines dedicated to the Virgin Mary (hence the name) which were located on a buildings' façade, often at an intersection; these were under the care of religious organisations, the noble family who owned the palace in question or the shopkeepers who could afford their upkeep and who, in most cases, had paid for them.

Despite the presence of such shrines, most streets in town were unlit and thus extremely dangerous.

Largely, European cities, in fact cities anywhere didn't have much in the way of public lighting before the early 19th century. The technological development that made public street lighting possible was the development of coal gas lamps in the late 18th century. Although I'm loathe to trust Wikipedia on this subject, my recollection is that by 1815 or so both Philadelphia and Baltimore had started rolling out gas-lit streetlamps.