Le Havre was founded on 8 October 1517 as a new port by royal command of Francis I of France, partly to replace the historic harbours of Harfleur and Honfleur which had become increasingly impractical due to silting-up. The city was originally named Franciscopolis after the king, and was subsequently renamed Le Havre-de-Grâce ("Harbour of Grace") after an existing chapel of Notre-Dame-de-Grâce ("our Lady of Grace"). The name of the American city of Havre de Grace, Maryland, is inspired by this name.

Before Francis I

Human presence on the territory of Le Havre dates back to Prehistory around 400,000 BC., Municipal Archives of Le Havre, consulted on 22 July 2012

Many remains from the Neolithic period have been excavated in the lower city and the :The Neolithic position of Fortins at Le Havre (Montgeon Forest), Louis Cayeux, Bulletin de la Société préhistorique de France, Vol. 60, No. 7-8, 1953, 426–431 pages, consulted on 22 July 2012 it is at this time that the population increased and settled down in the first hamlets. During the Iron Age Celtic people from Caletes settled in the region. From ancient times river traffic on the Seine supported Gallo-Roman cities of the estuary. A Roman road linked Lillebonne (Juliobona) at the mouth of the Seine through the current territory of the commune of Le Havre.

The first mention of Graville Abbey was in the 9th century,, Municipal Archives of Le Havre, consulted on 22 July 2012 about Sanvic on the plateau. The village of Leure and its commercial port appear in the 11th century.Claire Étienne-Steiner, Frédéric Saunier, Le Havre a port of new towns, 2005, éditions du patrimoine, p. 21 It served as a shelter for ships awaiting the tide to enter the port of Harfleur upstream. It was at this time that William Malet, companion of William the Conqueror built himself a castle at Graville and a Motte-and-bailey castle in Aplemont. Several hamlets of fishermen and farmers, the first parishes emerged in the High Middle Ages. During the Hundred Years War the fortified ports Leurre and Harfleur were destroyed. At the beginning of the 16th century, the growth of trade, the silting-up of the port of Harfleur, and the fear of an English landing pushed the king Francis I of France to found the port of Le Havre and the town.

The foundation of Le Havre

On 8 October 1517, King Francis I signed the founding charter of the port the plans of which are first assigned to Vice Admiral Guyon le Roy. The "big tower" defended the entrance. Despite difficulties associated with marshland and storms, the port of Le Havre welcomed its first ship in October 1518. The king himself travelled there in 1520 and granted in perpetuity the privileges of Le Havre and gave them his own arms consisting of a salamander., Municipal Archives of Le Havre, consulted on 22 July 2012 The military function was also encouraged: Le Havre was an assembly point for the French fleet during the wars. Ships also went fishing for cod in Newfoundland.

In 1525, a storm caused the death a hundred people, destroyed 28 fishing boats and the Chapel of Notre Dame. In 1536 the chapel was rebuilt in wood with stone pillars under the direction of Guillaume de Marceilles. A gothic tower with a large octagonal spire was added in 1540. The same year Francis I entrusted the planning and fortification project with Italian architect Girolamo Bellarmato. He had full power and organized the neighbourhood of Saint-François according to specific standards (grid plan, limiting the height of the houses, etc.). The first school and the granary were erected. The 1550s saw the creation of several municipal institutions: the town hall, the Amirauté (court of Justice), the hospital, the seat of the Viscounty and of the bailiwick.

The New World attracted adventurers and some left from Le Havre such as Villegagnon who founded a colony in Brazil (Fort Coligny) in 1555. At the end of the 16th century, trade expanded quickly and Le Havre saw the arrival of American products like leather, sugar, and tobacco. One of the main players in the traffic was an explorer and cartographer Guillaume Le Testu (1509–1573): a dock in Le Havre still bears his name.

On 20 April 1564 Le Havre became the port of departure for the French expedition of René Goulaine de Laudonnière to the New World where he created the first French colony at Fort Caroline near present-day Jacksonville, Florida. Famed artist Jacques le Moyne de Morgues joined Laudonnière on this colonizing effort and created the first known artistic depictions by a European of Native Americans in the New World, specifically the Timucua tribes in the modern-day areas of northeast Florida and southeast Georgia.

The wars of religion

The Protestant Reformation experienced relative success in Normandy. From 1557, John Venable, library colporteur from Dieppe disseminated in Pays de Caux and Lower Normandy the writings of Martin Luther and John Calvin.

Le Havre was greatly impacted by the Wars of Religion: On 8 May 1562 the reformers took the city, looted churches, and expelled Catholics. Fearing a counter-attack by the royal armies, they turned to the English who sent their troops. The occupants of the city built fortifications under the Treaty of Hampton Court. The troops of Charles IX, commanded by Anne de Montmorency, attacked Le Havre and the English were finally expelled on 29 July 1563. The fort built by the English was destroyed and the tower of the Cathedral of Notre-Dame was lowered on the orders of the King. He then ordered the construction of a new citadel which was completed in 1574. New fortifications were established between 1594 and 1610. In 1581 the construction began of a canal between Harfleur and the estuary of the Seine.

The first purpose-built Protestant church was constructed in Le Havre in 1600 in the district of Sanvic at 85 rue Romain Rolland. It was destroyed in 1685 on the revocation of the Edict of Nantes by Louis XIV. It was not until 1787 and the Edict of Versailles of King Louis XVI that Le Havre reopened a Protestant place of worship in the district of Saint-François.Charles Bost, Stories of Regional Protestant History, Vl. 1 : "Normandie", Union Fraternelle des Églises Réformées de Normandie, 1928 and Notes on Heritage No. 71, Le Havre, Éd. Momum, 2005

The 17th and 18th centuries

The defense function of Le Havre was reaffirmed and modernization of the port began in the 16th century on the orders of Cardinal Richelieu, governor of the city: the arsenal and the Roy Basin were developed, the walls were reinforced and a fortress built., Municipal Archives of Le Havre, consulted on 23 July 2012 It was in the latter that Cardinal Mazarin imprisoned the Fronde princes, Longueville, Conti, and Condé. At the beginning of the reign of Louis XIV, Colbert decided to renovate the port infrastructure and military: the work lasted 14 years. In 1669, the Minister inaugurated the Havre to Harfleur canal which is also called the "canal Vauban".

Le Havre affirmed its maritime and international calling during the 17th century: the Company of the Orient settled there in 1643. There were imports of exotic products from America (sugar, cotton, tobacco, coffee, and various spices). The slave trade enriched local traders especially in the 18th century. With 399 slave trade expeditions in the 17th and 18th centuries, Le Havre was the third largest French slave trade port after Nantes and La Rochelle.Olivier Pétré-Grenouilleau, The Slave Trade, Global Historical Essay, Paris, Gallimard, 2004, pp. 171–172 Maritime trade however is subject to international relations and a European context: the wars of Louis XIV and Louis XV momentarily interrupted the development of Le Havre. The Anglo-Dutch bombarded the city several times, notably in 1694 and in 1696.Michel de Boüard, History of Normandy, Toulouse, 2001 (), p. 284

In 1707 Michel Dubocage, a Captain from Le Havre, explored the Pacific Ocean aboard the Discovery and reached the Clipperton Island. Upon his return to Le Havre, he made his fortune by setting up a trading house and bought a mansion (now a Museum) in the heart of the Saint-François district and the lordship of Bléville. Another Captain from Le Havre Jean-Baptiste d'Après de Mannevillette (1707–1780) worked for the East India Company and mapped the coasts of India and China.

From the middle of the 18th century wealthy traders were building homes on the coast. In 1749 Madame de Pompadour wanted to see the sea and Louis XV chose Le Havre to satisfy her desire. The visit was ruinous to the city's finances.

In 1759, the city was the staging point for a planned French invasion of Britain – thousands of troops, horses and ships being assembled there – only for many of the barges to be destroyed in the Raid on Le Havre and the invasion to be abandoned following the naval defeat at the Battle of Quiberon Bay.

The economic boom of Le Havre resulted in an increase of its population (18,000 inhabitants in 1787, Municipal Archives of Le Havre, consulted on 23 July 2012 ) but also resulted in changes to the port and the city: the installation of a Tobacco Factory in the Saint-François district, the expansion of the shipyards, a new arsenal, and a commodity exchange. During a visit in 1786 Louis XVI approved the project to extend the city and it was François Laurent Lamandé he chose to take on the task of quadrupling the size of the city.

The French Revolutionary Period (1789–1815)

Between 1789 and 1793 the port of Le Havre was the second largest in France after that of Nantes. The Triangular trade continued until the war and its abolition. The port remained strategic because of the grain trade (supply of Paris) and its closeness to the British enemy.

The national events of the French Revolution were echoed in Le Havre: delegates for the List of Grievances were elected in March 1789., Municipal Archives of Le Havre, consulted on 23 July 2012 Popular riots occurred in July and the National Guard was formed some time later. A mayor was elected in 1790, the year of celebration of the Fête de la Fédération. The year 1793 was difficult for France and for Le Havre because of the war, federalist insurrections, and economic stagnation. The religious Terror transformed Notre Dame Cathedral into a Temple of Reason. The city acquired the status of sub-prefecture in the administrative reform of the Year VIII (1799–1800).Michel de Boüard, History of Normandy, Toulouse, 2001 () p. 398 Under the Empire Napoleon I came to Le Havre and ordered the construction of fortsMichel de Boüard, History of Normandy, Toulouse, 2001 () p. 408 A Chamber of Commerce was founded in 1800 but, because of the war against Britain and the continental blockade, port activity was reduced and activity of pirates increased. The population of Le Havre decreased to 16,231 inhabitants in 1815.

The prosperity of the 19th century