---
title: "Timeline of scientific discoveries"
chunk: 1/7
source: "https://en.wikipedia.org/wiki/Timeline_of_scientific_discoveries"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:28:31.534973+00:00"
instance: "kb-cron"
---

The timeline below shows the date of publication of possible major scientific breakthroughs, theories and discoveries, along with the discoverer.  This article discounts mere speculation as discovery, although imperfect reasoned arguments, arguments based on elegance/simplicity, and numerically/experimentally verified conjectures qualify (as otherwise no scientific discovery before the late 19th century would count). The timeline begins at the Bronze Age, as it is difficult to give even estimates for the timing of events prior to this, such as of the discovery of counting, natural numbers and arithmetic.
To avoid overlap with timeline of historic inventions, the timeline does not list examples of documentation for manufactured substances and devices unless they reveal a more fundamental leap in the theoretical ideas in a field.

== Bronze Age ==
Many early innovations of the Bronze Age were prompted by the increase in trade, and this also applies to the scientific advances of this period. For context, the major civilizations of this period are Egypt, Mesopotamia, and the Indus Valley, with Greece rising in importance towards the end of the third millennium BC. The Indus Valley script remains undeciphered and there are very little surviving fragments of its writing, thus any inference about scientific discoveries in that region must be made based only on archaeological digs. The following dates are approximations.

3000 BC: Units of measurement are developed in the Americas as well as the major Bronze Age civilizations: Egypt, Mesopotamia, Elam and the Indus Valley.
3000 BC: The first deciphered numeral system is that of the Egyptian numerals, a sign-value system (as opposed to a place-value system).
2650 BC: The oldest extant record of a unit of length, the cubit-rod ruler, is from Nippur.
2600 BC: The oldest attested evidence for the existence of units of weight, and weighing scales date to the Fourth Dynasty of Egypt, with Deben (unit) balance weights, excavated from the reign of Sneferu, though earlier usage has been proposed.
2100 BC: The concept of area is first recognized in Babylonian clay tablets, and 3-dimensional volume is discussed in an Egyptian papyrus. This begins the study of geometry.
2100 BC: Quadratic equations, in the form of problems relating the areas and sides of rectangles, are solved by Babylonians.
2000 BC: Pythagorean triples are first discussed in Babylon and Egypt, and appear on later manuscripts such as the Berlin Papyrus 6619.
2000 BC: Multiplication tables in a base-60, rather than base-10 (decimal), system from Babylon.
2000 BC: Primitive positional notation for numerals is seen in the Babylonian cuneiform numerals. However, the lack of clarity around the notion of zero made their system highly ambiguous (e.g. 13200 would be written the same as 132).
Early 2nd millennium BC: Similar triangles and side-ratios are studied in Egypt for the construction of pyramids, paving the way for the field of trigonometry.
Early 2nd millennium BC: Ancient Egyptians study anatomy, as recorded in the Edwin Smith Papyrus. They identified the heart and its vessels, liver, spleen, kidneys, hypothalamus, uterus, and bladder, and correctly identified that blood vessels emanated from the heart (however, they also believed that tears, urine, and semen, but not saliva and sweat, originated in the heart, see Cardiocentric hypothesis).
1800 BC: The Middle Kingdom of Egypt develops Egyptian fraction notation.
1800 BC – 1600 BC: A numerical approximation for the square root of two, accurate to 6 decimal places, is recorded on YBC 7289, a Babylonian clay tablet believed to belong to a student.
1800 BC – 1600 BC: A Babylonian tablet uses 25⁄8 = 3.125 as an approximation for π, which has an error of 0.5%.
1550 BC: The Rhind Mathematical Papyrus (a copy of an older Middle Kingdom text) contains the first documented instance of inscribing a polygon (in this case, an octagon) into a circle to estimate the value of π.

== Iron Age ==
The following dates are approximations.

700 BC: Pythagoras's theorem is discovered by Baudhayana in the Hindu Shulba Sutras in Upanishadic India. However, Indian mathematics, especially North Indian mathematics, generally did not have a tradition of communicating proofs, and it is not fully certain that Baudhayana or Apastamba knew of a proof.
700 BC: Pell's equations are first studied by Baudhayana in India, the first diophantine equations known to be studied.
700 BC: Grammar is first studied in India (note that Sanskrit Vyākaraṇa predates Pāṇini).
600 BC: Thales of Miletus is credited with proving Thales's theorem.
600 BC: Maharshi Kanada gives the ideal of the smallest units of matter. According to him, matter consisted of indestructible minutes particles called paramanus, which are now called as atoms.
600 BC – 200 BC: The Sushruta Samhita shows an understanding of musculoskeletal structure (including joints, ligaments and muscles and their functions) (3.V). It refers to the cardiovascular system as a closed circuit. In (3.IX) it identifies the existence of nerves.

== 500 BC – 1 BC ==
The following dates are approximations.