In reading a few books about the HRE, I see repeated mention that a territory’s or corporate group’s rights were “reconfirmed” by an emperor, treaty, pope, etc. Is this because rights, effectively, had to be personally guaranteed (i.e. enforced) by the current authority, and risked being revoked by the next regime change or political settlement, unless explicitly assured? And did such “reconfirmation” occur throughout the continent, or only in the irregular political amalgamation of the HRE?
This was a general feature of Late Medieval Europe, which reflected balance of power in overlapping jurisdictions.
At the pragmatic level, local authority - count, duke, king, bishop, Pope, urban magistrate, etc - wanted to extract as much revenue as was possible to justify by their customary rights. This way Italian merchants/bankers/pawnbrokers, (re)settling in Low Countries (14-16 centuries), had to buy licenses (charters) from the local count and from the authorities of the city they operated in. Licenses expired after stipulated period of time (typically more than 6 years).
In this case Italians, as would any other foreigners (Germans, Jews, etc), were entirely at the mercy of local authorities and had very little bargaining power. Expiration period here is indicative not of power relations, but of general business practices at the time. Renewed license accommodated changes in merchants' partnerships (some members left, another joined, business plan changed), adjustments to the previous terms (e.g. patching legal loopholes), adjustment to annual fees, paid to authorities (they were fixed, while inflation wasn't).
Another, more important scenario, is about French kings, granting various privileges and exemptions to the cities (14-16 centuries). Gradually, during the course of Hundred Years' War the king's right to impose regular direct taxes, to levy troops, to demand supplies and billeting -- became tolerated by cities. But, the king's capacity to enforce compliance varied significantly throughout his realm, and typically decayed with distance. So specific details of those obligations were subject to a fierce and incessant bargaining and lobbying between urban officials and the king.
King's negotiating arsenal included: exemptions from taxes, right to assess taxes, to distribute tax burden among local population, right to collect taxes, to divert part of them to local needs, exemption from troops levy, from billeting troops, from supplying victuals to the army on march, right of appeal to royal court, right to compensations for war damages, etc.
Granting exemptions and rights was ruler's principal way to incentivize those urban communities, which were too costly to force into obeyance. More or less it worked. The problem, however, arose when you grant them all. At this point all cities were happy, but the king was not, since he used up all his leverage.
Partly for this reason, most of the privileges were granted for a certain period of time, after which they had to be renewed. To restore his position the king might also revoke some privileges or trade them for others. In addition, he was always busy, devising new taxes just to outdate previous tax exemptions. To some extent the practice of re-negotiation was mutually beneficial, as each party hoped to come to better terms.
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