Task: Question Answering
Input (English): Passage: The stele is a late example of a class of donation stelae, which depicts the reigning monarch granting a tax exemption to the resident priesthood. Pharaohs had erected these stelae over the previous 2,000 years, the earliest examples dating from the Egyptian Old Kingdom. In earlier periods, all such decrees were issued by the king himself, but the Memphis decree was issued by the priests, as the maintainers of traditional Egyptian culture. The decree records that Ptolemy V gave a gift of silver and grain to the temples. It also records that there was particularly high flooding of the Nile in the eighth year of his reign, and he had the excess waters dammed for the benefit of the farmers. In return for these concessions, the priesthood pledged that the king's birthday and coronation days would be celebrated annually, and that all the priests of Egypt would serve him alongside the other gods. The decree concludes with the instruction that a copy was to be placed in every temple, inscribed in the "language of the gods" (hieroglyphs), the "language of documents" (demotic), and the "language of the Greeks" as used by the Ptolemaic government.Securing the favour of the priesthood was essential for the Ptolemaic kings to retain effective rule over the populace. The High Priests of Memphis—where the king was crowned—were particularly important, as they were the highest religious authorities of the time and had influence throughout the kingdom. Given that the decree was issued at Memphis, the ancient capital of Egypt, rather than Alexandria, the centre of government of the ruling Ptolemies, it is evident that the young king was anxious to gain their active support. Thus, although the government of Egypt had been Greek-speaking ever since the conquests of Alexander the Great, the Memphis decree, like the two preceding decrees in the series, included texts in Egyptian to show its connection to the general populace by way of the literate Egyptian priesthood.There exists no one definitive English translation of the decree because of the minor differences between the three original texts, and because modern understanding of the ancient languages continues to develop. An up-to-date translation by R. S. Simpson appears on the British Museum website, based on the demotic text. It can be compared with Edwyn R. Bevan's full translation in The House of Ptolemy (1927), based on the Greek text with footnote comments on variations between this and the two Egyptian texts. 
Question: Who were the highest religious authorities?
Output (English): High Priests of Memphis.