In this excerpt, ‘Greek’ means ‘Orthodox’ and ‘Latin’ refers to ‘Roman Catholics’.
The friars (dominicans and franciscans) injected a new element into the relations of the two churches, creating new tensions and holding out new possibilities. Time and agian, representatives of the Orthodox Church would find themselves at loggerheads with the friars. Their activities heightened concern among the Orthodox under Latin rule, whether in Constantinople, Cyprus, or even southern Italy and Sicily slipped below the horizon of Byzantine concern. The Greeks submitted fairly happily to Norman rule, while their monasteries benefited from Norman generosity. Recognition of papal primacy did not seem a terrible burden and was not allowed to interfere with the celebration of the Orthodox faith.
All this ended with the collapse of Norman rule in 1194. The minority of Frederick II was a decisive factor, allowing Pope Innocent III to interfere directly in the affairs of the Sicilian Church. He was prepared to tolerate Greek rites only in so far as the coincided with Latin practice. He forbade any concessions to the Greeks if they could involve spiritual dangers; a rider which gave the Latin clergy carte blanche to interfere in the affairs of the Greek Church…
Greek bishops were not to ordain Latin priests. The insistence that there could only be a single bishop for each diocese was on that favored the replacement of the few remaining Greek bishops in southern Italy by Latins. While Innocent III’s attack on the Greek Church was largely juridical, Pope Gregory IX questioned the validity of the Greek rite.
There were doubts about the Greek sacrament of teleiosis, which combined baptism and confirmation (chrismation). The Latin archbishop of Bari consulted the pope on the matter, with the result that, in November 1231, Gregory IX expressed his opinion that it was invalid, and that all Greeks would have to be rebaptized.
From Latins and Greeks in the Eastern Mediterranean After 1204, by Benjamin Arbel, Bernard Hamilton, David Jacoby, p. 70