ABSTRACT
At the end of the thirteenth century the ecclesiastical empire of Rome was the widest in territorial extent that up to that time had been obtained under any of the Pontiffs. With the exception of southern Spain, the Pope's rule was unquestioned throughout all Central and Western Europe. At the same time plans were being made continually to recapture the places lost in the East. 1 Not only were overtures for unification made with the Armenians, the Russians, and the Greeks; but missionaries were also sent to labour among the Mongols, the Mohammedans, the Persians, and the Chinese. Meanwhile the obligation to wage a holy crusade against all infidels and heretics was ever kept vividly before the imaginations of the Christian princes.
