Problems have arisen since the adoption of the United Nations Convention on the Law of the Sea (UNCLOS). If it is suggested that UNCLOS constitutes lex generalis it must be indicated that it cannot invalidate any rights arising under lex specialis such as the law of armed conflict, unless there is incontrovertible evidence in the text that it was intended to override such lex specialis. When deciding whether a ship was trading with an enemy port, or whether its cargo was intended for an adverse party, Prize Courts developed the doctrines of continuous voyage and ultimate destination. In maritime warfare only properly authorised combatants are permitted to participate in warlike activities. By Hague Convention VI enemy merchant ships in ports of the adverse party at the outbreak of hostilities were allowed to depart and were granted a period of grace for the purpose.