What have been decisive weapons?

[Oleander Ardens]

Artillery was cleary a weapon of ever increasing importance even in field battles, starting to make their mark in the first part of the 15th century, like in the battle of Castillion. A large numbers of guns became a conditio sine qua non for a strong army, as victory without strong artillery support seems to have been possible only if aided by surprise and terrain. See the Swiss confederation against Burgund.