Middot, Chapter One, Mishnah Three
1) There were five gates to the Temple Mount:
2) The two Huldah gates on the south were used both for entrance and exit;
3) The Kiponus gate on the west was used both for entrance and exit.
4) The Taddi gate on the north was not used at all.
5) The Eastern gate over which was a representation of the palace of Shushan and through which the high priest who burned the red heifer and all who assisted with it would go out to the Mount of Olives.
The Temple Mount had five gates, which the mishnah now lists.
Section one: Huldah was a prophetess mentioned in II Kings 22:14, but there is she found in Jerusalem, not necessarily at these gates. Perhaps these were the gates where she sat, albeit in the First Temple. We should note that one can still see these southern gates at the southern walls of the Temple. This seems to be the most common entrance and exit.
Section two: We dont really know who Kiponus was. It is possible that he was the man who donated the gate.
Section three: The Taddi gate on the north was rarely used. One exception will be brought at the end of this chapter. Again, Taddi seems possibly to have been the man who donated the gate.
Section four: Over the eastern gate was a drawing of Shushan, Per sia. This was in commemoration of the place where the Jews were during the exile. It might have also served as a tribute to Cyrus who let the Jews leave Persia to return to Israel. To the east of the Temple lies the Mount of Olives, where the red heifer was burned. The high priest and the other priests involved in this ceremony would go through this gate on their way to the Mount of Olives to burn the red heifer.