Across
1
Medieval land-for-service system
4
Practice of establishing foreign colonies
5
Armored warrior of medieval times
6
Metal that replaced bronze in tools
9
Armed entry into another territory
11
Formal agreement between nations
12
Fortified medieval residence
Down
2
Deadly epidemic disease
3
Sudden overthrow of a government
7
Person who travels to discover new lands
8
Large territory under one ruler
10
Legislative assembly of a country
12
Advanced stage of human society