Meaning any indication of the future (especially favorable) is from 1650s; earlier (1630s) in extended sense of benevolent influence of greater power, influence exerted on behalf of someone or something, originally in expression under the auspices of.
The King of Prussia Mall is located in the community of King of Prussia in Upper Merion Township, Montgomery County, Pennsylvania, 20 miles (32 km) northwest of Philadelphia.
There could not be a king of Brandenburg, which was part of the Empire, and there could not be a king of Prussia, because part of it was in Poland. By an ingenious formula, however, Frederick was permitted to call himself king in Poland.