Complex sentence: About 12,000 appear to have entered Navarre, where they were allowed to remain, but under the pressure of the kings of Spain both the newcomers and the Navarrese Jews that didn't convert to Catholicism were expelled from the kingdom in 1498.
Split into simpler sentences: About 12,000 appear to have entered Navarre, where they were allowed to remain. Under the pressure of the kings of Spain both the newcomers and the Navarrese Jews that didn't convert to Catholicism were expelled from the kingdom in 1498.