The first three heads of the dispute between Latins and Greeks listed by Erasmus involve complex issues. The fifth century had seen bitter disputes about the correct usages of the terms 'nature' and 'hypostasis' (which Latin theology came to translate as 'person') when applied to Christ and the Trinity. The Council of Chalcedon made it necessary after 451 to speak of one nature and three persons in God, but one person and two natures in Christ. Unhappily, the meaning of both terms was still shifting at the time of the definition and there are examples of orthodox thought expressed subsequently-in heterodox terminology and heterodox thought expressed in orthodox terminology. The Latins argued on the second point the procession of the Holy Spirit from Father and Son (adding the word Filioque to the Creed), which the Greeks rejected. It is a mark of Latin theology to reject the term 'generation' applied to the Holy Spirit and to insist on 'procession'. On the third point, the Latins attached much less importance than the Greeks to the function in the rite of consecration of the invocation to the Holy Spirit or 'epiclesis'. For centuries indeed the Roman rite contained no explicit epiclesis.