Leiria is a city and a municipality in the Centro Region of Portugal. It is the capital of Leiria District. The population in 2011 was 126,879, in an area of 565.09 km². The city proper has about 50,000 inhabitants. It is the seat of the Roman Catholic Diocese of Leiria-Fátima.
The region around Leiria has been inhabited for a long time, although its early history is obscure. The first evident inhabitants were the Turduli Oppidani, a Celtiberian tribe (akin to the Lusitanians), who established a settlement near (around 7 km) present-day Leiria. This settlement was later occupied by the Romans, who expanded it under the original Celtiberian name Collippo. The stones of the ancient Roman town were used in the Middle Ages to build much of Leiria.
The name "Leiria" in Portuguese derives from leira (from the medieval Galician-Portuguese form laria, from proto-Celtic *?l?r-yo-, akin to Old Irish làr ground, floor, Breton leur ground, Welsh llawr floor) meaning an area with small farming plots. It was occupied by the Suebi in 414 and later incorporated by Leovigild into the Visigoths kingdom in 585 A.D. Later the Moors occupied the area until it was captured by the first King of Portugal, Afonso Henriques in 1135, during the so-called Reconquista. The settlement was intermittently attacked until 1140. South of Leiria in that period was the so-called "no-mans land", until regions further south (like Santarém and Lisbon) were permanently taken and re-populated by the Christians. In 1142 Afonso Henriques gave Leiria its first foral (compilation of feudal rights) to stimulate the colonisation of the region.
Both Afonso I of Portugal and Sancho I rebuilt the walls and the Leiria Castle to avoid new enemy incursions. Most of the population lived inside the protective city walls, but already in the 12th century part of the population lived outside the walls. The oldest church of Leiria, the Church of Saint Peter (Igreja de São Pedro), built in romanesque style in the last quarter of the 12th century, served the parish located outside the walls.
During the Middle Ages the importance of the village increased, and it was the setting of several cortes (feudal parliaments). The first of the cortes held in Leiria took place in 1245, under King Afonso II. In the early 14th century, King Dinis I restored the keep tower of the citadel of the castle, as can be seen in an inscription in the tower. He also built a royal residence in Leiria (now lost), and lived for long periods in the town, which he donated as feud to his wife, Isabel. The King also ordered the plantation of the famous Pine Forest of Leiria (Pinhal de Leiria) near the coast. Later, the wood from this forest would be used to build the ships used in the Portuguese Navigations of the 15th and 16th centuries.
In the late 14th century, King John I built a royal palace within the walls of the castle of Leiria. This palace, with elegant gothic galleries that offered wonderful views of the town and surrounding landscape, was totally in ruins but was partially rebuilt in the 20th century. John I also sponsored the rebuilding in late gothic style of the old Church of Our Lady of the Rock (Igreja de Nossa Senhora da Pedra), located inside the castle.
Towards the end of the 15th century the town continued to grow, occupying the area from the castle hill down to the river Lis. King Manuel I gave it a new foral in 1510, and in 1545 it was elevated to the category of city and became see of a Diocese. The Cathedral of Leiria was built in the second half of the 16th century in a mix of late manueline and mannerist styles.
Compared to the Middle Ages, the subsequent history of Leiria is of relative decadence. The city was stormed by the Peninsular War, namely in 1808 (the killing of Portela, by the troops of Gen. Margaron) and the Great Fire of 1811, caused by the Napoleonic troops retreating from the Lines of Torres Vedras. In the 20th century, however, its strategic position in the Portuguese territory favoured the development of a diversified industry.
Leiria is located in the Centro Region and sub region of Pinhal Litoral, about halfway between Lisbon and Porto. The distance to Lisbon is 137 kilometres (85 miles), to Coimbra 70 kilometres (43 miles) and to Porto 177 kilometres (110 miles). The historic city centre spreads between the castle hill and the river Lis.
Leiria is also included in the Região de Leiria. As the main city in this community, the area of influence of Leiria spreads over the cities of Marinha Grande, Ourém, Alcobaça, Fátima, Pombal as well the municipalities/town seats of Batalha, Porto de Mós and Nazaré located nearby.
As well as being a site of historical interest, the Castle of Leiria provides a venue for cultural events . Situated close to the castle, the Church of Saint Peter (Igreja de São Pedro) is used as the venue of Leirias annual festival of music. Leiria is also home to m|i|mo , Portugals only Museum of the Moving Image and the Paper museum  (Museu do moinho do papel) situated at the site of Portugals first paper mill. The Theatre Miguel Franco in the market SantAna (Mercado de SantAna) and The Theatre José Lúcio da Silva  are venues for theatre, music and dance performances, as well as cinema.
The city is the birthplace of several leading Portuguese poets, such as Afonso Lopes Vieira and Francisco Rodrigues Lobo, after whom the central square is named. Today the square is home to a thriving café culture, as well as being regularly used for cultural events. Other poetes: The King D.Dinis (Denis of Portugal) and the writer Eça de Queiroz who wrote his first realist novel, O Crime do Padre Amaro ("The Sin of Father Amaro"), which is set in the city and was first published in 1875. There are also Film and TV adaptations.
The city has several cultural associations and bookshops who give presentations of cultural and artistic projects, with Bookshop Arquivo and Cultural Association Célula Membrana offering the busiest calendar of events.
In recent years, Leiria has seen much re-development to the banks of the river Liz . These developments have created several new parks, public spaces, childrens play areas and a series of themed bridges. Additionally, a long promenade has been created which is popular with both walkers and joggers.
There are several summer Festivals held in the region. The town hosts a monthly antiques market.