In the Elthos world the older the magic the more powerful it may be. The rational is that over time as man invented technology (which is the thing I have as getting better and better over time) the need for magic was displaced, and so the magic began to become less powerful. So Titanium Steel replaces, over time, the need for the Magical Sword. For one thing, technology is much easier to produce, once the science of the technique is understood. But magic is mysterious, and a lot of magic was never understood by the practitioners - the knowelege was on loan from Celestial Beings. Thus, sorcerers like Media or Cerces would contract with the Gods for magic, and the Gods alone understood how the magic worked. In the advance of civilization, as man's technology improved, the advantages of magic were reduced, and the total cost of obtaining it become less and less worth the effort.

Before, in the old days, a sorcerer might have to sacrifice quite a few virgins to gain access to the magic of shielding from fire. Virgins were of course problematic to obtain, and could land you (or your king) in a good deal of trouble and potentially lead to war, which could destroy everything. Later, resistance to fire was invented by technologies such as asbestos. This could be mass produced. It therefore causes the magic to become less worth the cost. In addition, man found out that science builds on itself like Lego Blocks, so that the more he discovers about basic science the greater the general benefits to mankind. And consequently magic became less and less valuable because it could not be mass produced. So in my world, which is currently running somewhere in the early medieval era (ie - just before the advent of science), so magic is still used, and still popular, but has become less effective due to all of the minor advances of civilization up to the current time. There used to be spells needed to make the crops grow, for example, and the Earth Goddess had to be appeased for the corn to rise. But now, most people have forgotten the old ways, and the crops grow because they understand more about how farming works than their forefathers who started out not understanding much about the life cycle of crops. So now they water their crops consistently, take the stones from the soil using plows, and gain better yields by switching crops every other year. The need for the Earth Goddess to bless the crops is lessened. Some still follow the old ways, of course, and bemoan greatly "the new fangled" ways that people have adopted, and fret that the world will come to a bad end since the people have forgotten the Gods. They may be right.

So the magic of the old days, in Elthos, was the most powerful for two reasons. First the magic was freshly minted by the powers of the Elkron (Celestials) themselves - which is the most powerful of all magic. Later on down the ages, the mortals began to learn how to conduct magic themselves, but it was never as powerful as what the Elkron could create, and this was a later generation of magic. Still powerful, but not as powerful as the earlier magic. Later, magic devolves into parlor tricks, sparkly trinkets and magical toys because the sacrifices needed to make Greater Magic was no longer worth the cost. The oldest items of power, in fact, have incredible histories, and those who wielded them were "the mighty ones of old". To find such an artifact in my world is a pretty big deal. That kind of magic can be unpredictable, and exercise widely diverse powers as it is touched by the Gods, and contains a kind of mystical energy that is more pure that what the mortals could produce. So when someone finds an old tumulus in Elthos, and it contains artifacts of power (assuming the tomb was not raided some time in the distant past), then the possibilities are pretty much endless as to what kinds of magic might be found, and the powers thereof. But going to the local apothecary and obtaining a potion, or scroll, or charm is likely to be far less powerful or enduring.

The corollary is that older magic tends to be much better guarded than anything else. The Elkron themselves might protect certain artifacts which are sacred to them. Or assign other beings to protect them. Or build traps that are more likely than not to do the job. Thus, from an adventurer's point of view, digging into old things has a certain rational. It can be highly profitable. And so risking the danger is worth the effort if you can survive and walk away with some item of ancient power. On the other hand, some items of ancient power are buried / hidden / protected because the power within them is not only great - but evil, or highly destructive, or chaotic.

One example is the story of a chest in the temple of the Sun that contains a cloth. The temple guards the chest with everything it has, and it is hidden deep in the bowels of the temple and guarded constantly. Only an invading army with wizards and powerful priests could possibly get to the chest. And once they do, if the should open it, things might not go so well for them. The cloth is very powerful. Of course I won't spoil things by saying here what it is, but some people might be able to guess.