When I was studying Charles V, it was said that he gave control of his army in the one of the Italian wars to Charles Bourbon. However he neglected to pay the army and this was one of the causes of the sack of Rome. So was Charles Bourbon required to pay the army as he was commander? Was Bourbon paid directly by the emperor or was it simply a titular honour? Some other dukes under Charles V seemed to have bankrupted themselves from paying for his armies, but I don't see why that is their responsibility? Thanks in advance!
A reply to /u/Kotoro7
Good timing, this is fresh off another post a few minutes ago.
Closer to 1700, soldiers during the 80YW and 30YW (1550s to 1650s) were notoriously brutal, partly due to the inability of their erstwhile state employers to provide for them, thus they tend to "help themselves" so to speak and ransack the place where they are located or billeted.
Here I spoke a bit about how this came to play in the military revolution. Here I spoke on how difficult it was to get funding in the first place, let along send them to the right place. And here I spoke of the infamous Sack of Antwerp, where soldiers whose pay was in arrears for years mutinied.
Soldiers became infamous for their cruelty and methods of exacting loot and payment, and in German lexicon they still ring to today.
Logistics was a major issue even for victors of great battles. The Swedish army had to continue to insist that her allies pay and provide for the upkeep of the Swedish army, lest they ransack the states of her own allies!
There are occasional lights of brilliance in logistics, however. Wallenstein the greatest military contractor of all time set up a state-across states with a sophisticated taxation and tribute system to prevent looting. The Army of Flanders was periodically supplied with fresh troops up the Spanish Road, and in most cases the daily bread was something they could rely on.
In the 16th century there was no fluid, reliable banking and credit system that we know today, so in many endeavors even the wealthiest royals have to rely on private parties to put up with the upfront cost, in exchange for either nobility, land grant, or some other financial obligation.
A notable example is the Palatine - Low Countries campaign of Ambrogio Spinola in 1620s, who used his vast family's fortune to raise an army, fund its campaign northwards to the Low Countries, and had to wait years before any reward was dispensed by the Spanish crown. The strategic situation in western HRE, the Rhine, and the Low Countries, was deteriorating and the Spanish Habsburg needed to mount an offensive. But they could not do so themselves directly. They had find an agent, such as Ambrogio Spinola, to basically fund, organize, and execute the endeavor, for an uncertain promise that they would be sufficiently rewarded in the future.
This was not new. When the Duke of Alba marched 10,000 Spanish veterans from Italy to the Low Countries in the 1560s, he too had to put up with much of the cost upfront.
Nearly all enterprises of early modern europe required a private party to put up with the cost up-front. Even something as seemingly simple as sending already acquired funds to another location, requires somebody on the other side to front the money, and then be paid at a later time (or some other suitable due reward).
This practice also permeated across all levels of command and exercise. Captains are expected to pay for the needs of their men out of pocket when money wasn't forthcoming from the treasury. If they themselves get into financial trouble, then their Colonels are expected to step in. And so on and so forth.
As to their reward and motive, it varies. Loot can be very rich. When Mantua was sacked, it was said the victors made off with millions of florins. At smaller scale, tolls paid as extortion can be valuable in important trade areas. Contractors are also in asiento, a form of short term high interest loans. Finally, there are nobility titles and estates to be endowed.