When writing the history of Sankt Peterburg one must be careful in details;
1) The city privileges were granted in 1642. Pjotr I conquered the city and the whole of ingria and just built a new fortification on Jänissaari, the present day petro-Pavlovskij Krepost. The myth of 1703 founding of the city was created in mid 1850s in Pansalvist fervor - with magical "divine eagle" etc.
2) The "siege of Leningrad" never was, because Finland never took part on it. Thus, supplies were coming to the city during the whole "siege" and e.g. taks exported to other fronts form Leningrad factories.
3) The famine of the city was caused byt the fact, that originally the city was to be abandoned and all food supplies were evacuated. Only due to insubordinance of Zhdanov Leningrad decided to fight instead of surrendering. Stalin intended to give it to the German army without a fight.