Responsa על מגילה 51:26

Q. A donated a plot of ground to the community for the purpose of erecting a synagogue thereon. However, when the members of the community made ready to build the synagogue they were restrained by the "students of Jesus" (probably theological students). The community, therefore, decided to build a Talmudical school instead; whereupon A objected that he did not donate the ground for such purpose.
A. Since A did not originally stipulate the condition that in case a synagogue is not built on said ground, it shall revert to him, he may no longer withdraw his gift, and the ground belongs to the community who can use it for any purpose it sees fit. The mere designation of an object for a sacred purpose does not sanctify the object, and it may still be used for a secular purpose. Therefore, were A not a resident of that town, the community would be free to use said ground for building the school. But if A is a resident of that town, since a community can not use for one purpose, community property originally designated for another purpose, unless such change be unanimously approved by the members of the community, or approved by a resident, outstanding scholar of the caliber of R. Ashi, the community can not build a school on the ground, since the protest of A does not permit a unanimous approval of the plan. Therefore, the community can do nothing with the ground till either the Christian priests permit them to build a synagogue, or A withdraws his objection.
This Responsum is addressed to "My teacher Rabbi Asher."
SOURCES: Am II, 240; Mord. Meg. 821. Cf. Agudah B.B. 21.