At the same time the rapid and remarkable success of Grotius's treatise (De jure belli et pacis) brought his view of Natural Right into prominence, and suggested such questions as - " What is man's ultimate reason for obeying these laws?
Among Whewell's other works - too numerous to mention - reference must be made to writings popular in their day, such as the Bridgewater Treatise on Astronomy (1833), and the essay, Of the Plurality of Worlds (1854), in which he argued against the probability of planetary life, and also to the Platonic Dialogues for English Readers (1859-1861), to the Lectures on the History of Moral Philosophy in England (1852), to the essay, Of a Liberal Education in General, with particular reference to the Leading Studies of the University of Cambridge (1845), to the important edition and abridged translation of Grotius, De jure belli et pacis (1853), and to the edition of the Mathematical Works of Isaac Barrow (1860).
But the church was thereby involved in a double conflict; for while on the one hand the Novatianist schism represents the puritan outcry against such laxity, on the other the martyrs (not indeed for the first time) claimed a position above church law, and gave trouble by issuing libelli pacis, i.e.
Reverting to the distinction in Roman law, Grotius and Pufendorf, with many others, treat protection as an instance of unequal treaties; that is, " when either the promises are unequal, or when either of the parties is obliged to harder conditions " (De jure belli et pacis, 1 C. 13.21; De jure naturae, 8.
The taking of oaths, the assigning of " conservatores pacis " and the giving of hostages are now obsolete, but revenue is mortgaged, territory is pledged, and treaties of guarantee are entered into for this purpose.