Climate: It is located in a temperate climate. In this classification, most C and D climates are temperate. Mostly: Cfb, Cfc, Dfa, Dfb, Dsa, Dsb, Dwa, Dwb. And also, Csa, and Csb.
Technology level: European middle age (late middle age to be more precise)
Result: A big city with several thousand people: 50 000-100 000 +
Process: How can I achieve a high population?