This judgment is the more interesting as being in distinct conflict with the opinion of the bishop of Rome - Leo - who, departing from the policy of his predecessor Celestine, had written very strongly to Flavian in support of the doctrine of the two natures and one person.
Strontium sulphate, SrSO 4, found in the mineral kingdom as celestine, is formed when sulphuric acid or a soluble sulphate is added to a solution of a strontium salt.
Henry, skilfully winning over Pisa, Genoa and the Roman Commune, isolated Tancred and intimidated Celestine III., who, on the 14th of April 1191, crowned him emperor at Rome.
In 431 he appeared in Rome to interview Pope Celestine regarding the teachings of St Augustine and then all traces of him are lost until 440, the first year of the pontificate of Leo I., who had been in Gaul and thus probably had met Prosper.
He also induced Pope Celestine to publish an Epistola ad episcopos Gallorum against Cassian.