The Hilltop Castle building design was simply defined as – a castle of a Fort built onto a hill or plateau top. This served many defensive functions. Generally steep hillsides would practically eliminate siege weapons as an option for attack. Hilltop structures also provided excellent observation capabilities to observe enemy troop movements. In addition, (especially with the advent of gunpowder and cannon), Hilltop structures provided an excellent platform for fire (both defensive and support capabilities). The sheer height of some Hilltop forts and castles also provided a form of enhancement to the local Lord. Hilltops Castles were the most expensive to build and maintain. The huge cost of construction and materials transport in such an extreme environment was cost prohibitive to all by the most wealthy of Lords or Kings. Another drawback was in a garrison's troop positioning. With a large area for staging or preparation, cavalry was difficult to maintain in and around a Hilltop Castle. Early 13th Century Frankish and Germanic Kingdoms favored Hilltop structures. Basic design and other innovations (Towers, etc), were still left up to the builder (taking into account for terrain and cost). These structures were constructed out of regional stone (often from the very Hilltop being used).