The mandate of the International Mediator in Bosnia and Herzegovina has been an evolving process that began shortly after the Federation of Bosnia and Herzegovina was established by the Washington Agreements. 

The Mediator's mandate originated in the difficulties presented in establishing the local institutions of the Federation of Bosnia and Herzegovina.  Initially, the international community foresaw arbitration as the method to facilitate a lasting peace process and resolve disputes.

Arbitration was first mentioned in the Bonn-Petersberg Agreement of 10 March 1995 regarding the establishment of municipal and cantonal institutions.  It said, "Should agreement not be reached by 1 April 1995 the issue shall be decided by arbitration or constitutional court."  However, the arbitration decisions were binding and had no recourse to appeal.  Local parties tend to be dissatisfied with the outcome, as they had no influence in the decision process.

Bosnian President Izetbegović and Croatian President Tudjman agreed on a method for resolving disputes that allowed the local parties to negotiate their differences through mediation.  If this failed, then the issue would be forwarded to a binding arbitration process.  A plan was drawn up, with the consent of the German and US governments, in which Dr. Christian Schwarz-Schilling served as mediator and Mr. Roberts Owen as arbitrator.  The title of Federation Mediator is first mentioned specifically in the "Agreed Minutes of the 16-18 May 1995 Mostar Meeting", know as the Mostar Agreement. 

The plan was approved whereby the Mediator would concentrate on unresolved political issues to be solved through mediation, and the Arbitrator would resolve legal questions through binding arbitration.  Both Dr. Schwarz-Schilling and Mr. Owen were designated their titles respectively.  The mandate was reconfirmed three times in international documents:

1. "Friends of the Federation of Bosnia and Herzegovina "Statement on 24 October 1995.  The parties recognised the work of the Federation Mediator and asked him "to continue to review contentious issues regarding the implementation of the Federation." 
2. The Petersberg Declaration on the Federation of Bosnia and Herzegovina of 25 April 1996 reaffirmed support for the efforts "concerning the resolution of disputes within the Federation" of both the Federation Mediator and the Federation Arbitrator and called "on all those concerned to respect fully and implement the letter and spirit of their decisions."
3. The Bonn Peace Implementation Conference 1997 "called on the authorities in Bosnia and Herzegovina, in particular the Entities, to make use of the instrument of international mediation in order to resolve disputes concerning the implementation of the Peace Agreement.  It commended the work already undertaken in this field by the current Federation Mediator." 

The Bonn Peace Implementation Conference statement became the basis for the Federation Mediator to approach authorities in Republika Srpska with the offer of mediation services.  The then President of Republika Srpska, Mrs. Biljana Plavšić, accepted the offer and agreed to allow mediation to commence in Republika Srpska. Prime Minister Milorad Dodik also confirmed his acceptance of mediation services in February 1998.  With acceptance of the legitimacy of mediation efforts by both entities, Dr. Schwarz-Schilling was officially recognised as the International Mediator for the Federation of Bosnia and Herzegovina and Republika Srpska.  With time, and due to the length of the name, the title was shortened to International Mediator in Bosnia and Herzegovina.