Although the details are lost in time, a closer look at the ancient mythology surrounding their worship will help us understand how pagan practices have survived in popular Easter customs.
Two of the earliest recorded deities were the Babylonian fertility god Tammuz and the goddess Ishtar. Every year Tammuz "was believed to die, passing away from the cheerful earth to the gloomy subterranean world" (Sir James Frazer, The Golden Bough, 1993, p. 326).
The seasonal cycle came to be connected with Tammuz's supposed annual death and resurrection. "Under the names of Osiris, Tammuz, Adonis, and Attis, the peoples of Egypt and Western Asia represented the yearly decay and revival of life ... which they personified as a god who annually died and rose again from the dead. In name and detail the rites varied from place to place: in substance they were the same" (p. 325).
Many of these rites revolved around inducing the return of Tammuz from the dead. One of these ceremonies is recorded in Ezekiel 8:14 Ezekiel 8:14Then he brought me to the door of the gate of the LORD's house which was toward the north; and, behold, there sat women weeping for Tammuz.
American King James Version×, where Ezekiel saw in vision an abominable sight: women "weeping for Tammuz" at the very temple of God.
The Expositor's Bible Commentary says regarding this verse: "Tammuz, later linked to Adonis and Aphrodite by name, was a god of fertility and rain ... In the seasonal mythological cycle, he died early in the fall when vegetation withered. His revival, by the wailing of Ishtar, was marked by the buds of spring and the fertility of the land. Such renewal was encouraged and celebrated by licentious fertility festivals ... The women would have been lamenting Tammuz's death. They perhaps were also following the ritual of Ishtar, wailing for the revival of Tammuz" (Ralph Alexander, Vol. 6, 1986, pp. 783-784).
As worship of Tammuz and Ishtar spread to the Mediterranean region, including the territory of biblical Israel, the pair came to be worshiped under other names: Baal and Astarte (Ashtoreth), Attis and Cybele, and Adonis and Aphrodite. God heatedly condemned the sensual, perverted worship of Baal and Astarte, the "Queen of Heaven" (Judges 2:11-15 Judges 2:11-15  And the children of Israel did evil in the sight of the LORD, and served Baalim:
 And they forsook the LORD God of their fathers, which brought them out of the land of Egypt, and followed other gods, of the gods of the people that were round about them, and bowed themselves to them, and provoked the LORD to anger.
 And they forsook the LORD, and served Baal and Ashtaroth.
 And the anger of the LORD was hot against Israel, and he delivered them into the hands of spoilers that spoiled them, and he sold them into the hands of their enemies round about, so that they could not any longer stand before their enemies.
 Wherever they went out, the hand of the LORD was against them for evil, as the LORD had said, and as the LORD had sworn to them: and they were greatly distressed.
American King James Version×; Judges 3:7-8 Judges 3:7-8  And the children of Israel did evil in the sight of the LORD, and forgot the LORD their God, and served Baalim and the groves.  Therefore the anger of the LORD was hot against Israel, and he sold them into the hand of Chushanrishathaim king of Mesopotamia: and the children of Israel served Chushanrishathaim eight years.
American King James Version×; Judges 10:6-7 Judges 10:6-7  And the children of Israel did evil again in the sight of the LORD, and served Baalim, and Ashtaroth, and the gods of Syria, and the gods of Zidon, and the gods of Moab, and the gods of the children of Ammon, and the gods of the Philistines, and forsook the LORD, and served not him.  And the anger of the LORD was hot against Israel, and he sold them into the hands of the Philistines, and into the hands of the children of Ammon.
American King James Version×; 1 Kings 11:4-33 1 Kings 11:4-33  For it came to pass, when Solomon was old, that his wives turned away his heart after other gods: and his heart was not perfect with the LORD his God, as was the heart of David his father.  For Solomon went after Ashtoreth the goddess of the Zidonians, and after Milcom the abomination of the Ammonites.  And Solomon did evil in the sight of the LORD, and went not fully after the LORD, as did David his father.  Then did Solomon build an high place for Chemosh, the abomination of Moab, in the hill that is before Jerusalem, and for Molech, the abomination of the children of Ammon.  And likewise did he for all his strange wives, which burnt incense and sacrificed to their gods.  And the LORD was angry with Solomon, because his heart was turned from the LORD God of Israel, which had appeared to him twice,  And had commanded him concerning this thing, that he should not go after other gods: but he kept not that which the LORD commanded.  Why the LORD said to Solomon, For as much as this is done of you, and you have not kept my covenant and my statutes, which I have commanded you, I will surely rend the kingdom from you, and will give it to your servant.  Notwithstanding in your days I will not do it for David your father's sake: but I will rend it out of the hand of your son.  However, I will not rend away all the kingdom; but will give one tribe to your son for David my servant's sake, and for Jerusalem's sake which I have chosen.  And the LORD stirred up an adversary to Solomon, Hadad the Edomite: he was of the king's seed in Edom.  For it came to pass, when David was in Edom, and Joab the captain of the host was gone up to bury the slain, after he had smitten every male in Edom;  (For six months did Joab remain there with all Israel, until he had cut off every male in Edom:)  That Hadad fled, he and certain Edomites of his father's servants with him, to go into Egypt; Hadad being yet a little child.  And they arose out of Midian, and came to Paran: and they took men with them out of Paran, and they came to Egypt, to Pharaoh king of Egypt; which gave him an house, and appointed him victuals, and gave him land.  And Hadad found great favor in the sight of Pharaoh, so that he gave him to wife the sister of his own wife, the sister of Tahpenes the queen.  And the sister of Tahpenes bore him Genubath his son, whom Tahpenes weaned in Pharaoh's house: and Genubath was in Pharaoh's household among the sons of Pharaoh.  And when Hadad heard in Egypt that David slept with his fathers, and that Joab the captain of the host was dead, Hadad said to Pharaoh, Let me depart, that I may go to my own country.  Then Pharaoh said to him, But what have you lacked with me, that, behold, you seek to go to your own country? And he answered, Nothing: however, let me go in any wise.  And God stirred him up another adversary, Rezon the son of Eliadah, which fled from his lord Hadadezer king of Zobah:  And he gathered men to him, and became captain over a band, when David slew them of Zobah: and they went to Damascus, and dwelled therein, and reigned in Damascus.  And he was an adversary to Israel all the days of Solomon, beside the mischief that Hadad did: and he abhorred Israel, and reigned over Syria.  And Jeroboam the son of Nebat, an Ephrathite of Zereda, Solomon's servant, whose mother's name was Zeruah, a widow woman, even he lifted up his hand against the king.  And this was the cause that he lifted up his hand against the king: Solomon built Millo, and repaired the breaches of the city of David his father.  And the man Jeroboam was a mighty man of valor: and Solomon seeing the young man that he was industrious, he made him ruler over all the charge of the house of Joseph.  And it came to pass at that time when Jeroboam went out of Jerusalem, that the prophet Ahijah the Shilonite found him in the way; and he had clad himself with a new garment; and they two were alone in the field:  And Ahijah caught the new garment that was on him, and rent it in twelve pieces:  And he said to Jeroboam, Take you ten pieces: for thus said the LORD, the God of Israel, Behold, I will rend the kingdom out of the hand of Solomon, and will give ten tribes to you:  (But he shall have one tribe for my servant David's sake, and for Jerusalem's sake, the city which I have chosen out of all the tribes of Israel:)  Because that they have forsaken me, and have worshipped Ashtoreth the goddess of the Zidonians, Chemosh the god of the Moabites, and Milcom the god of the children of Ammon, and have not walked in my ways, to do that which is right in my eyes, and to keep my statutes and my judgments, as did David his father.
American King James Version×; 1 Kings 16:30-33 1 Kings 16:30-33  And Ahab the son of Omri did evil in the sight of the LORD above all that were before him.  And it came to pass, as if it had been a light thing for him to walk in the sins of Jeroboam the son of Nebat, that he took to wife Jezebel the daughter of Ethbaal king of the Zidonians, and went and served Baal, and worshipped him.  And he reared up an altar for Baal in the house of Baal, which he had built in Samaria.  And Ahab made a grove; and Ahab did more to provoke the LORD God of Israel to anger than all the kings of Israel that were before him.
American King James Version×; 1 Kings 22:51-53 1 Kings 22:51-53  Ahaziah the son of Ahab began to reign over Israel in Samaria the seventeenth year of Jehoshaphat king of Judah, and reigned two years over Israel.  And he did evil in the sight of the LORD, and walked in the way of his father, and in the way of his mother, and in the way of Jeroboam the son of Nebat, who made Israel to sin:  For he served Baal, and worshipped him, and provoked to anger the LORD God of Israel, according to all that his father had done.
American King James Version×; 2 Kings 23:13 2 Kings 23:13And the high places that were before Jerusalem, which were on the right hand of the mount of corruption, which Solomon the king of Israel had built for Ashtoreth the abomination of the Zidonians, and for Chemosh the abomination of the Moabites, and for Milcom the abomination of the children of Ammon, did the king defile.
American King James Version×; Jeremiah 7:18 Jeremiah 7:18The children gather wood, and the fathers kindle the fire, and the women knead their dough, to make cakes to the queen of heaven, and to pour out drink offerings to other gods, that they may provoke me to anger.
American King James Version×).
Pre-Christian customs linked to Christ
In ancient worship we find the mythology that would ultimately link these ancient customs to Christ's death and resurrection. Says Alan Watts: "It would be tedious to describe in detail all that has been handed down to us about the various rites of Tammuz, Adonis,... and many others... But their universal theme—the drama of death and resurrection—makes them the forerunners of the Christian Easter, and thus the first ‘Easter services.' As we go on to describe the Christian observance of Easter we shall see how many of its customs and ceremonies resemble these former rites" (Easter: Its Story and Meaning, 1950, p. 58).
Watts describes some of the similarities and parallels: "Shortly before the vernal [spring] equinox ... the members of this cult [of Tammuz-Ishtar, Attis-Cybele and Adonis-Aphrodite] began a fast—as Christians also have the fast of Lent, beginning forty days before Easter."
He tells how some worshippers would cut down a tree, then carry it "with reverence and ceremony to Cybele's temple and set it up in the central sanctuary" There, "upon its central stem [trunk], was hung the figure of the young god" (p. 59).
"Here, for the remaining days of the fast, the worshipers gathered to sing hymns of mourning for the dead Attis ... And to this day, on Good Friday at the Veneration of the Cross, Christians sing their hymn of mourning for another and greater one who died on a Tree ..." (p. 59).
As the fast drew to an end, a remarkable rite took place: "The figure of the dead Attis was taken down from the tree and buried under the twilight sky. Far into the night his devotees stood around the grave and sang hymns of mourning. But as dawn approached, a great light was kindled, as today Christians light the Paschal Candle on Easter Eve as a symbol of the risen Christ" (pp. 61-62).
Frazer describes the idolatrous worship this way: "The sorrow of the worshippers was turned to joy ... The tomb was opened: the god had risen from the dead; and as the priest touched the lips of the weeping mourners with balm, he softly whispered in their ears the glad tidings of salvation. The resurrection of the god was hailed by his disciples as a promise that they too would issue triumphant from the corruption of the grave. On the morrow ... the divine resurrection was celebrated with a wild outburst of glee. At Rome, and probably elsewhere, the celebration took the form of a carnival" (p. 350).
An ancient celebration adopted
In its various forms, worship of Tammuz-Adonis-Attis spread around the Roman Empire including to Rome itself. As Christianity spread through the empire, religious leaders apparently merged customs and practices associated with this earlier "resurrected" god and applied them to the resurrected Son of God.
Says Frazer: "When we reflect how often the Church has skillfully contrived to plant the seeds of the new faith on the old stock of paganism, we may surmise that the Easter celebration of the dead and risen Christ was grafted upon a similar celebration of the dead and risen Adonis" (p. 345).
In this respect Easter followed the pattern of Christmas in being officially sanctioned and welcomed into the church. As Frazer goes on to say: "Motives of the same sort may have led the ecclesiastical authorities to assimilate the Easter festival of the death and resurrection of their Lord to the festival of the death and resurrection of another Asiatic god which fell at the same season. Now the Easter rites still observed in Greece, Sicily and southern Italy bear in some respects a striking resemblance to the rites of Adonis, and I have suggested that the Church may have consciously adapted the new festival to its heathen predecessor for the sake of winning souls to Christ" (p. 359).
To discover what God thinks of merging customs associated with worship of other gods with worship of Him, be sure to read "Does It Matter to God?".