Inter caetera

The date on the parchment

The bull bears the formal date 4 May 1493, at St Peter's in Rome. Papal-chancery evidence shows that this second Inter caetera was in fact prepared and expedited in June.

Nothing demonstrable changed on 4 May. The revised bull was expedited in June, reached Spain before a certified copy was made at Barcelona on 19 July, and that copy was sent to Columbus on 4 August.

The line, and what came with it

Alexander VI granted Ferdinand and Isabella and their heirs and successors as kings of Castile and León jurisdiction over islands and mainlands found or to be found westward and southward beyond a pole-to-pole demarcation line.

That line was described — awkwardly — as 100 leagues 'towards the west and south' from any of the islands commonly called the Azores and Cape Verde, a formula that could not be plotted as one unambiguous modern longitude.

Lands already in the actual possession of a Christian ruler by Christmas 1492 were excluded from the grant.

The conditions attached

The bull ordered the monarchs to send qualified instructors in the Catholic faith, and prohibited unauthorised travel or trade beyond the line under threat of excommunication. Columbus was praised by name, and his first voyage's reported discoveries supplied the immediate setting.

The first Inter caetera, formally dated 3 May, had granted only lands discovered by Castilian agents and safeguarded conflicting Christian rights more generally. After receiving it, Ferdinand and Isabella sought a more favourable replacement.

Documentary scholarship traces the revised provisions to those Castilian requests, and finds no evidence that Alexander acted as an impartial referee.