It is probable that in the beginning, as the result of limited observation and speculation, the number of gods in the Babylonian pantheon was relatively small. However, in the course of time, {167} they became greatly multiplied as the result of a wider observation of the phenomena of nature, political changes, and theological speculation. Over against this tendency to multiply deities there shows itself, in the course of the centuries, a tendency to diminish the number of gods, and in the end comparatively few remain, until in the late Babylonian period the worship seems to have been confined chiefly to Marduk, Nabu, Sin, Shamash, and Ishtar. Some of the great thinkers of Babylonia seem to have gone even so far as to consider the various deities manifestation of the one god Marduk. There is in existence a tablet of the Neo-Babylonian period which states that Marduk is called Ninib as the possessor of power, Nergal as lord of battle, Bel as possessor of dominion, Nabu as lord of business, Sin as the illuminator of the night, Shamash as the lord of right, Addu as the lord of rain, etc.[6] It is seen, then, that monotheistic tendencies are not absent from the Babylonian religion. But they never go beyond the realm of speculation. "The Babylonians, with all their wonderful gifts, were never able to conceive of one god, of one god alone, of one god whose very existence makes logically impossible the existence of any other deity. Monotheism transcends the spiritual grasp of the Babylonian mind."[7] In the words of Delitzsch, "Notwithstanding all this, however, and despite {168} the fact that many liberal and enlightened minds openly advocated the doctrine that Nergal and Nebo, that the moon-god and the sun-god, the god of thunder, Ramman, and all the rest of the Babylonian pantheon, were one in Marduk, the god of light, still polytheism, gross polytheism, remained for three thousand years the Babylonian state religion--a sad and significant warning against the indolence of men and races in matters of religion, and against the colossal power which may be acquired by a strongly organized priesthood based upon it."[8] Even the most spiritual expressions of the Babylonian religion, the so-called penitential psalms, bear witness to the fact that the writers continued to worship many deities. In one of the most spiritual of these psalms, the psalmist prays: That the heart anger of my lord be appeased, A god unknown to me be appeased, A goddess unknown to me be appeased, A known and unknown god be appeased, A known and unknown goddess be appeased, That the heart of my god be appeased, The heart of my goddess be appeased, God and goddess, known and unknown, be appeased.[9]