XV. Of the same kind is the promise given by the Romans, that Carthage should be free, which could never mean the enjoyment of complete independence, by a people, who had long before lost the right of making war, and many of their other privileges. Yet it left them some degree of liberty, so much at least, that they should not be obliged to remove the seat of their government at the command of any foreign power, and gave them a pledge that their city should not be disturbed. It was in vain then for the Romans to urge that it was only the city which was intended. Whereas those acquainted with the use of metaphorical language know that by the city is frequently meant the inhabitants, and government with its privileges, and not the mere walls and houses. For the term, BEING LEFT FREE, implies that the people should enjoy their own laws. XVI. The nature of personal and real treaties is a frequent subject of inquiry, which may properly be examined in this place. Indeed in all transactions with a free people, the engagements entered into with them are of a real nature; because the subject of them is a permanent thing. So permanent, that, although a republican be changed into a regal government, a treaty will remain in force: for the political body continues the same, although the head be changed, and the sovereign power, which before was diffused among many members, is now centered in one. Yet this rule will admit of an exception, where it is evident that the specific form of government made an essential part of the treaty, as when two states make a federal union for the mutual preservation of their political systems. But if a treaty be made with a KING OR SOVEREIGN PRINCE, it does not consequently follow that it is to be considered only as a PERSONAL and not a REAL treaty. For the name of a person may be inserted in a treaty, not merely to give it the character of a personal treaty, but to point out the contracting parties. And this will be still more evident, if, as is usual in most treaties, a clause is annexed declaring it to be perpetual, or made for the good of the kingdom, or with the king himself, and his successors, and it will also be considered as a real treaty, even if it is stated to be passed for a definite time. The treaty between the Romans and Philip, King of the Macedonians, seems to have been of this description, which, upon the refusal of his son to continue it, gave rise to a war.