Bows
From Crusaderkings
province_event = {
id = 3000
name = "TECH_DISCOVERY"
map = yes tag = shortbow
picture = event_techinvention
trigger = { condition = { type = capital value = yes }
condition = { type = not value = { type =
has_advance value = { shortbow = yes } } }
condition = { type = advance_focus value = shortbow } }
mean_time_to_happen = {
months = 50