Responsa על כתובות 104:20

A. Why did you inquire of me concerning matters of taxation which are rooted in local custom, each community being governed by its own customs? The Talmud states that a person may withdraw from a partnership without the consent of the other partners when each person is attacked by a band of robbers and thus may suffer a loss of money (B. K. 116b). Therefore, if the Jews of Friedberg were accustomed to be partners in payment of normal taxes only, A had a right to withdraw from the partnership with reference to the exorbitant tax which constituted outright robbery. The rule, "the law of the land prevails", does not apply to extraordinary taxation, the latter being considered outright robbery. Therefore, since A warned the community to include him in their settlement with the authorities only if he was to bear the burden of the ensuing tax in proportion to the money he had left after paying his debts, the leaders of the community had no right to include him in their settlement unless they agreed to his terms. They should have excluded A's wife from their settlement with the authorities. However if such exclusion of A's wife might have led to her being abused and defiled by the uncircumcised — for a report reached us of the Jews of Friedberg having been threatened that unless they speedily come to terms with their captors their wives would be outraged and defiled — the leaders of the community were justified in including her in the general settlement in spite of A's protests. A Jew should be ransomed and delivered out of the hands of Gentiles even against his express will, and should be charged with the expenses incurred. Moreover, if the Jews of Friedberg were accustomed to be partners even in the payment of exorbitant taxes — for the custom in these kingdoms has been for a long time that there were no normal taxes, and every overlord levied taxes to his heart's content — the mere fact that the tax was more exorbitant than the others did not give A the right to withdraw from the partnership. Every tax levied by the overlord must be borne proportionately by all the Jews of the community. Even though A warned the leaders not to include him in the general agreement, except on his terms, his warning was of no avail as long as the leaders did what they thought the right thing. Since in the opinion of the latter it was better to come to terms with the government instead of passively revolting against it, A was bound by the act of these leaders and must contribute his share in proportion to the capital he possessed at the time of the arrest. The fact that he was later forced to repay his debts did not diminish his obligation; for this obligation was not created at the time the agreement was reached with the authorities, but it was created at the time of the arrest, and at that time he still possessed seventy marks. A's complaint that some of the members of the community evaluated their immovables and books at less than their actual value, is irrelevant, for the community members have done him a favor by paying a tax on such valuables. Had they refused to pay such tax, no court would have compelled them to pay it. Already in former generations, many persons had complained bitterly before the courts and had demanded that immovables and books be taxed, especially when exorbitant taxes were demanded by the authorities — taxes that took away nine tenths of one's capital — but the owners of immovables and books were always acquitted in accordance with a long established custom instituted by the "ancients" [early settlers of Germany and France]. Since many good reasons, as well as the interests of public welfare, support the decision that immovables are not taxable, no court can override the decision of the other courts in this matter, unless the people of your community originally unanimously adopted a different ruling, for a community may change an established custom by a unanimous vote only. Regarding the alleged promise of the rich tax-payer to A, I have little to say as long as the promisor keeps silent. In any case, since the promise was not made formally, the promisor has a right to change his mind at any time. However, A's complaint that the community leaders have foregone certain obligations of some members, is a serious complaint since the leaders have no right to forego A's part of such tax obligations without his consent. But if these leaders were originally unanimously elected freely to manage the affairs of the community, and were thus vested with the power to forego obligations to the community whenever they would see fit to do so, they have acted well within their rights.
R. Meir adds: It is true that I was inclined to derive from the aforementioned talmudic sources the rule that immovables be assessed at one quarter their value, but the long established custom of not taxing such property prevails even in the face of talmudic law. Your arguments for not taxing books are conclusive.
SOURCES: Am II, 127–8. Cf. Mord. B. B. 480; Agudah B. B. 20; Israel Bruno, Responsa 123; Terumat Hadeshen 341; ibid. 342.