The tablet in the above image is know as the Venus Tablet of Ammisaduqa from the Neo-Assyrian period. The tablet is on display in the British Museum, London. Image Credit: Wikipedia contributor "Fæ"
The celestial body which we now call Venus was known to ancient Indian, Greek, Egyptian, Babylonian and Chinese observers. The early Greeks actually thought they were recording the movements of two different objects — one that appeared in the morning and one that appeared in the evening. Their "evening star" was called Hesperus (in Greek mythology, a son of the dawn goddess Eos) and their "morning star" was called Phosphorus (also a son of Eos and brother to Hesperus) The Greek philosopher and mathematician Pythagoras is credited with realizing these two object were one and the same.
Venus was important to ancient American cultures, in particular for the Maya, who called it Noh Ek, "the Great Star" or Xux Ek, "the Wasp Star"; they embodied Venus in the form of the god Kukulkán (also known as or related to Gukumatz and Quetzalcoatl in other parts of Mexico). In the in the Mayan book which we now call the Dresden Codex, the Maya charted Venus' full cycle.
For their times, these culture made careful records of Venus. But even so, there is no evidence that any of these ancient cultures knew of the transits of Venus across the sun.
The next transit of Venus will occur over June 5-6. To learn more, visit these links.
2012 Transit of Venus, NASA/Goddard Space Flight Center: eclipse.gsfc.nasa.gov/OH/transit12.html
Transit of Venus, Sun-Earth Day 2012, NASA: sunearthday.nasa.gov/transitofvenus/