 Arbitration is another operator to fuse knowledge bases that has been introduced in the early Nineties (Revesz 1993, Liberatore and Schaerf 1995). In belief revision, it is commonly assumed that the new information is accepted and must be included in the revised base. By contrast, arbitration addresses situations in which two sources give contradicting information but are equally reliable (examples are two equally competent experts, two equally trustworthy witnesses etc.). If we have no reason to dismiss one of the two sources, the solution is to fuse the two bases rather than revise one by the other. The operation is arbitration in the sense that, since both sources are equally reliable, the resulting base should contain as much as possible of both sources. Liberatore and Schaerf (1995) proposed axioms for arbitration between two belief bases, and the operator proposed by Revesz only satisfied some of them. Their proposal suffered from the fact of being limited to the arbitration of only two bases. This limitation is overcome in the belief merging approach, where a finite number of bases can be merged into a consistent one.