code:

trigger = {
		owner = {
			ai = no
			has_focus = focus_rulership
			is_ruler = yes
			is_tribal = no
			wealth = 400
			NOT = { has_character_flag = architect_offer }
		}
		has_empty_holding = yes
		NOT = { has_global_flag = rulership_castle }
	}
	
	mean_time_to_happen = {
		months = 280
	}
	
	immediate = {
		owner = { set_global_flag = rulership_castle }
		if = {
			limit = { 
				owner = { job_treasurer = { stewardship = 5 } }
			}
			random_list = {
				75 = { 
					owner = { 
						character_event = { id = WoL.12003 }
						set_character_flag = architect_offer
					}
				}
				25 = { 
					owner = { 
						character_event = { id = WoL.12002 }
						set_character_flag = architect_offer
					}
				}
			}
		}
		if = {
			limit = {
				NOT = { owner = { job_treasurer = { stewardship = 5 } } }
			}
			owner = {
				character_event = { id = WoL.12001 }
				set_character_flag = architect_offer