This post aims to explain briefly the historical evolution and key aspects of patent law from privileges granted in the Middle Age to modern rules set up by the World Trade Organization (WTO).
The first forms of exclusive protection were not patents as known in modern times, but they came in the form of privileges, which were granted by the crown. Famously, King Henry III granted in 1236 to Bonofusus de Sancta Columba a 15 years exclusive privilege to make fabrics of various colour in Bordeaux. In 1331, Edward III granted Letter of Protection to John Kempe, a Flemish weaver, in order to encourage foreign craftsmen to settle in England. But it was until 1421 that the first modern patent was granted to Filippo Brunelleschi for a ship for transporting, loading and unloading objects, such as marble, on a river. So far, it can be observed that those privileges could be granted either to activities such as trading or inventing, e.g. Brunelleschi’s machine.
Inventions such as the one of Brunelleschi led to regions in Europe to issue more comprehensive protection on inventions such as the Venetian Patent Statute, which precisely prized the effort of inventors in the economic development of the city. The act established that
There are men in this city, and also there come other persons every day from different places by reason of its greatness and goodness, who have most clever minds, capable of devising and inventing all kinds of ingenious contrivances. And should it be legislated that the works and contrivances invented by them could not be copied and made by others so that they are deprived of their honour, men of such kind would exert their minds, invent and make things that would be of no small utility and benefit to our State.
Despite the fact of the efforts carried out by the city of Venice, the Statute was hardly enforceable.
It was until the English Statute of Monopoly of 1624 that efforts to protect inventive activity begun to be recognised not by the fact that the King wanted to grant particular protection to an activity, but by the fact that an invention fulfilled specific requirements. The Statute of Monopoly ruled out monopolies as they were considered to be against common law. Patents for inventions were an exception of the Statute. The Statute granted 14 years patent protection to those inventions that were “new manufacture”, such a requirement sought to protect more the inventive activity itself rather than the interest of the King to protect a specific activity. England kept leading such a transformation via different reforms in XIX century that included granting powers to patent examiners (not to the King) and creating simpler and easier procedures to obtain or lost a patent (The Patents, Designs and Trade Marks Act of 1883).
But it was the US Patent Act that brought us closer to our modern patent system as the US Constitution (Section 8) demanded the congress to create exclusive rights to inventors: “To promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries.”
Although there were important developments in different countries on the creation of comprehensive patent legislation, there was a concern regarding the limit scope that patent protection gave to inventors since patents were granted locally, which means that an inventor have to apply for a patent in each country following diverse rules in different countries. This led countries, particularly developed ones to enact the Paris Convention on Industrial Property and the Paris Union (which eventually become the World Intellectual Property Organization (WIPO)) in order to harmonise national paten laws. The Paris Convention set up basic principles for the international harmonisation of patents. First, it creates the national treatment provision, which involves that each member of the Paris Convention shall grant the same protection to nationals of other members that it grants to its own nationals (Article 2). Second, right of priority which consist in when an applicant fill for an application (first application) in one of the country members of the Paris Convention, the applicant may, within 12 months, file subsequent applications for patent protection in any of the other country members (Article 4.A). This means that other States member should consider the subsequent applications as they were filed on the same day as the first application. The expression “right of priority”, hence, is a legal fiction that involves that there is a priority over applications filed by others during the said period of time for the same invention. Third, independence of the patent which consists that a patent that has been granted in a member of the Paris Convention would not necessarily require that other member should grant a patent (Article 4 bis). Four, right to be named as an inventor, which means that even if an inventor gives up her economic rights, it should be recognised as such in the patent application (Article 4 ter). Finally, Paris Convention rules the use of compulsory licensing (Article 5); this is a legal mechanism in which States can grant to a third party the use of patent without the authorization of patent owner providing that the latter has been previously paid off and there is a process to obtain the compulsory licence, in which the patent owner takes part.
Later on, the WTO linked international trade with IPRs, including patents, in order to provide further harmonisation via the Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPs). TRIPs brings three main principles: (i) national treatment which is basically the same as the Paris Convention (Article 3); (ii) Most Favoured Nation (MFN) which requires members of the WTO not to discriminate other members, for example, you cannot give term of 20 years patent protection to one country, and 25 to another (Article 4); and (iii) balance protection which means that the protection of IP should also contribute to technical innovation and the transfer of technology (Article 7); both producers and users of technology should benefit, and economic and social welfare should be enhanced. TRIPs also establishes, for the case of patents that there should be patents for any inventions, whether products or processes, in all fields of technology, provided that they are new, involve an inventive step and are capable of industrial application. It also states that countries can exclude some inventions from patent protection such as for methods of treatment of humans or, plants or animals, inventions against order public or moral (Article 27).
The evolution of the patent law illustrates how this system of exclusivity protection went from privileges granted on King’s interest to a global and harmonise system that responds to the interest of certain countries, particularly developed ones, in protecting their industries in new markets.
 For further information on Privileges in the Middle Age see: Martin Kretschmer, Lionel Bently and Ronan Deazley (eds), Privilege and Property (OpenBook Publisher 2010).
 Bruce W. Bugbee, ‘Genesis of American Patent and Copyright Law’ (1967) in Michael F Martin, ‘The End of the First-To-Invent Rule : A Concise History of Its Origin’ (2009) 49 Idea.
 Ronan Deazley, ‘Commentary on the Statute of Monopolies 1624’ in L Bently and Martin Kretschmer (eds), Primary Sources on Copyright (1450-1900) (www.copyrighthistory.org 2008).
Frédéric Rideau, ‘Commentary on the Déclaration Royale on Privileges Granted to Inventors (1762)’ in Lionel Bently and Martin Kretschmer (eds), Primary Sources on Copyright (1450-1900) (www.copyrighthistory.org 2008).
 Chris Dent, ‘“Generally Inconvenient”: The 1624 Statute of Monopolies as Political Compromise’ (2009) 33 Melbourne University Law Review.
 For further information on the Paris Convention see: GHC Bodenhausem, Guide to the Application of the Paris Convention for the Protecion of Industrial Property as Revised at Stockholm in 1967 (United International Bureaux for the Protection of Intellecual Property 1967).