July 11, 1687

Philosophiæ Naturalis Principia Mathematica

Printing of Newton's Principia completed

Newton's masterpiece nearly became collateral damage from the Royal Society's expensive, poorly selling book about fish — Edmond Halley paid the printing costs himself.

5 July 1687: 'I have at length brought your book to an end'

On 5 July 1687, Edmond Halley wrote to Isaac Newton that he had finally brought Newton's book to completion — the documentary basis for dating the finished printing of the Philosophiae naturalis principia mathematica to that day. The 11 July date is not supported by the specialist evidence and appears to be a calendar-entry error.

The Latin first edition was printed in London by Joseph Streater under the authority of the Royal Society, whose president Samuel Pepys had signed the imprimatur — dated 5 July 1686, a year before completion, which is why the 'Julii 5' in the book's front matter is not itself the publication date.

Halley gets Newton's book through the press

The Royal Society ordered the work printed but could not finance it. Halley — who had prompted the project with a 1684 conversation about the mathematical consequences of an inverse-square attraction — managed the manuscript through the press, corrected proofs and diagrams, and underwrote the costs himself.

The finished three-book treatise presented the laws of motion and applied its mathematical principles to gravitation, planetary and cometary motion, the Moon, tides, resisting media, waves, and sound.

Into the book trade

With printing complete, the first edition could enter the trade in early July 1687; Halley transferred copies to booksellers and promoted the work, including copies intended for continental Europe. Newton revised it for second and third editions in 1713 and 1726.

How many were printed is a live question: earlier estimates placed the run near 250 copies, but a 2020 census identified 387 surviving first-edition copies and concluded the original run must have been larger.

Sources

Researched 23 Aug 2026 6 sources 3 audit passes Date disputed

How this was checked

Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →

Date disputed. Sources disagree; the research places it at 1687-07-05.

What the sources leave uncertain

July 11 is not supported by the specialist evidence consulted and should be removed.
July 5 is the date of Halley's letter announcing that the book had been brought to an end, so it securely dates completion of printing. Treating it as a modern, sharply defined retail 'publication day' is less certain; scholarly work also describes the book as appearing in early July.
The 'Julii 5' printed in the book's front matter belongs to Samuel Pepys's 1686 imprimatur and is not itself a 1687 publication date.
Earlier estimates placed the print run near 250 copies, but a 2020 census found 387 surviving copies and concluded that the original run must have been larger.