Periodic table (detailed cells)
Although precursors to this table exist, its invention is generally credited to Russian chemist Dmitri Mendeleev in 1869. Mendeleev invented the table to illustrate recurring ("periodic") trends in the properties of the elements. The layout of the table has been refined and extended over time, as new elements have been discovered, and new theoretical models have been developed to explain chemical behavior.
Iguvine Tablets
The Iguvine Tablets, also known as the Eugubian Tablets or Eugubine Tables, are a series of seven bronze tablets from ancient Iguvium (modern Gubbio), Italy. The earliest tablets, written in the native Umbrian alphabet, were probably produced in the 3rd century BC, and the latest, written in the Latin alphabet, from the 1st century BC. The tablets contain religious inscriptions that memorialize the acts and rites of the Atiedian Brethren, a group of 12 priests of Jupiter with important municipal functions at Iguvium. The religious structure present in the tablets resembles that of the early stage of Roman religion, reflecting the Roman archaic triad and the group of gods more strictly related to Jupiter. Discovered in a farmer's field in the year 1444, they are currently housed in the Civic Museum of the Palazzo dei Consoli in Gubbio.