The government's income came from five principal sources: regular taxes, occasional taxes, fines, income taxes, miscellaneous taxes and tributes from feudatories. An emergency tax was imposed occasionally and were applicable when the kingdom was under duress, such as when it faced natural calamities, or was preparing for war or overcoming war's ravages. Income tax included taxes on crown land, wasteland, specific types of trees considered valuable to the economy, mines, salt, treasures unearthed by prospectors. Additionally, customary presents were given to the king or royal officers on such festive occasions as marriage or the birth of a son.