Saint-Omer is a commune in France. It is a commune and sub-prefecture of the Pas-de-Calais department west-northwest of Lille on the railway to Calais. The town is named after Saint Audomar, who brought Christianity to the area.
The canalised portion of the river Aa begins at Saint-Omer, reaching the North Sea at Gravelines in northern France. Below its walls, the Aa connects with the Neufossé Canal, which ends at the Lys River.
Adjacent to Saint-Omer (or St. Omer) is the community of Haut-Pont (Haute Ponte), the historic Belgian and much earlier, the various French-Netherlands boundary in a number of centuries. There is a small but evident West Flemish influence in the town. Saint-Omer has also some older speakers of Picard or Ch'ti(mi) who are organizing to preserve the language.
Saint-Omer first appeared in the writings during the 7th century under the name of Sithiu (Sithieu or Sitdiu), around the Saint-Bertin abbay founded on the impulsion of Audomar (Audomarus, Odemaars or Omer).
Omer, bishop of Thérouanne, in the 7th century established the Abbey of Saint Bertin, from which that of Notre-Dame was an offshoot. Rivalry and dissension, which lasted till the French Revolution, soon sprang up between the two monasteries, becoming especially virulent when in 1559 St Omer became a bishopric and Notre-Dame was raised to the rank of cathedral.
In the 9th century, the village that grew up round the monasteries took the name of St Omer. The Normans laid the place waste about 860 and 880. Ten years later the town and monastery had built fortified walls and were safe from their attack.
Situated on the borders of territories frequently disputed by French, Flemish, English and Spaniards, St Omer long continued subject to siege and military invasions. In 1071 Philip I and Count Arnulf III of Flanders were defeated at St Omer by Robert the Frisian. In 1127 the town received a communal charter from William Clito, count of Flanders. In 1340 a large battle was fought in the town's suburbs between an Anglo-Flemish army and a French one under Eudes IV, Duke of Burgundy, in which the Flemish force was forced to withdraw.
In 1493 the town became part of the Low Countries and under Spanish dominion for more than 170 years. The French made futile attempts against it between 1551 and 1596. During the Thirty Years War, the French attacked in 1638 (under Cardinal Richelieu) and 1647.
Finally in 1677, after seventeen days' siege, Louis XIV forced the town to capitulate; and the peace of Nijmegen permanently confirmed the conquest and its annexation by France. In 1711 St Omer, on the verge of surrendering because of famine, was saved by the daring of Jacqueline Robin, who risked her life to bring provisions into the town.
The College of Saint Omer was established in 1593 by Fr Robert Persons SJ, an English Jesuit, to educate English Catholics. After the Protestant Reformation, England had established penal laws against Catholic education in the country. The college operated in St Omer until 1762, when it migrated to Bruges and then to Liège in 1773. It finally moved to England in 1794, settling at Stonyhurst, Lancashire. Former students of the College of Saint Omer include John Carroll, his brother Daniel and his cousin Charles.