Conflation of Resurrection Gods Tammuz, Adonis, and Osiris
“In later times, after the revolt of Egypt from the Assyrian king and the rise of the 26th Dynasty, the cult of Adonis at Gebal entered upon a new phase.
Egyptian beliefs and customs made their way into Phoenicia along with Egyptian political influence, and the story of Adonis was identified with that of the Egyptian Osiris. As the Sun-god Osiris had been slain and had risen again from the dead, so, too, had the Phoenician Adonis descended into Hades and been rescued again from its grasp.

Osiris on a lapis lazuli pillar in the middle, flanked by Horus on the left and Isis on the right (22nd dynasty, Louvre, Paris).
Public Domain
Uploaded by Borislav
Created: between 874 and 850 BC (Twenty-second dynasty)
Guillaume Blanchard, Own work, July 2004,
Osiris, Isis and Horus: pendant bearing the name of King Osorkon II
http://en.wikipedia.org/wiki/Osiris#/media/File:Egypte_louvre_066.jpg
How long, indeed, he had remained in the world below was a matter of doubt. There were some who said that he shared half the year with the goddess of death, and the other half only with the goddess of love; there were others who declared that his year was divided into three–four months was he condemned to dwell in Hades, four months he was free to live where he might choose, while the other four were passed in the companionship of Ashtoreth, and that it was to Ashtoreth that he devoted his months of freedom.
But all agreed that the Sun-god of spring was not compelled to live for ever in the gloomy under-world; a time came when he and nature would alike revive. It was inevitable, therefore, that in the days of Egyptianising fashion, Adonis and Osiris should be looked upon as the same god, and that the festival of Adonis at Gebal should be assimilated to that of Osiris in Egypt.
And so it came about that a new feature was added to the festival of Adonis; the days of mourning were succeeded by days of rejoicing; the death of Adonis was followed by the announcement of his resurrection.
A head of papyrus came from Egypt over the waves; while, on the other hand, an Alexandrian legend told how the mourning Isis had found again at Gebal the chest in which the dismembered limbs of Osiris were laid.
It is clear that the Babylonian poet who sang of the descent of Istar into Hades had no conception of a festival of joy that followed immediately upon a festival of mourning. Nevertheless, the whole burden of his poem is the successful journey of the goddess into the under-world for the sake of the precious waters which should restore her beloved one to life.
Even in Babylonia, therefore, there must have been a season when the name of Tammuz was commemorated, not with words of woe, but with joy and rejoicing. But it could have been only when the fierce heats of the summer were past; when the northern wind, which the Accadians called “the prospering one,” began again to blow; and when the Sun-god regained once more the vigour of his spring-tide youth.
That there had once been a festival of this kind is indicated by the fact that the lamentations for his death did not take place in all parts of Syria at the same time. We learn from Ammianus that when Julian arrived at Antioch in the late autumn, he found the festival of Adonis being celebrated “according to ancient usage,” after the in-gathering of the harvest and before the beginning of the new year, in Tisri or October.
It must have been in the autumn, too, that the feast of Hadad-Rimmon was observed, to which Zechariah alludes; and Ezekiel saw the women weeping for Tammuz in “the sixth month.” Nay, Macrobius even tells us that the Syrian worshippers of Adonis in his time explained the boar’s tusk which had slain the god as the cold and darkness of winter, his return to the upper world being his “victory over the first six zodiacal signs, along with the lengthening day-light.”
A.H. Sayce, Lectures on the Origin and Growth of Religion as Illustrated by the Religion of the Ancient Babylonians, 5th ed., London, 1898, pp. 229-31.