The first reference about the Mosterio Gully dates from the population permit of La Selva del Camp, in 1164. In 1204 the place was part of the territory known as 'Teus el loco ocato Mosterium', and in 1565 the place was known as 'Moster', name that is still used nowadays by the people in the region. In 1204 the feudal lord of Reus, Benet de Bell-lloc, ceded two thirds of the place to Bartomeu del Moster, recording that the place was part of Reus. This same year an open defiance arised between the two lords and asked the chamberlain to pass judgement. The sentence recognised the right of Almoster to have its own mayor, and also to pay taxes to Reus in exchange. Despite the seeming agreement the disputes continued until 1206 when the chamberlain bought the lordship of Almoster. When the chamberlain's sway over the place finished Almoster and Reus finally signed an agreement with the following terms: Almoster recognised the place was a quarter built in the township of Reus which meant they would have to pay 12 pounds in concept of taxes. The agreement was valid until 1717 due to the establishment of the decree of Nova Planta. In 1621, Archbishop Joan de Montcada confirmed this subordination, he had been Lord and Baron of the place since the extintion of thhe chamberlainship and delegated the civil and criminal jurisdiction to the mayor of Reus. Owing to the construction of the Prior house , Reus decided to compel all its inhabitants to pay their period of duty, on the contrary they would have to pay the wage of a substitute. This rule also included Castellvell and Almoster, both suffragan of Reus.

In the Middle Ages, a Jewish colony lived in the fortified town of Almoster, still nowadays the name of three portals reminds us of its fortified origin. The first census from 1497 counted up 12 families and this number went up to 18 in 1515 and 24 in 1553 but again fell to 18 in 1563. The growing of hazelnut trees, started around 1520, probably gave a positive impulse, since, from that time, the population gradually increased.

In 1573, Archbishop Gaspar Cervantes de Gaeta authorised Almoster to have a holy water font which avoided the danger of taking the new born to Reus, he also ordered the Prior to travel to Almoster and christianise the babies.

Also in the Middle Ages, our mayor had some confrontations with La Selva about the pasture fields and with Reus about the water supply. The problems were solved with the signing of two pacts, one in 1428 and the other in 1480.

In 1527, the town was scene for a tragic story. Some bandits kidnapped Andreu Pàmies and his servant, both from Almoster, and took them to a farmhouse, there they beheaded the servant and sent his head to the town, when they did not get the expected ransom they also killed Pàmies.

There is not much information about the wars in the 17th century but, in 1625, the town requested 8 harquebuses to defend themselves against any possible attack. The population growth kept going up, in 1708 Almoster had 41 houses, 68 in 1719, 75 in 1763 and 84 in 1787. In this same year of 1787, the temple finally became a parish church. All along the 18th century, Almoster stayed over the archbishop's sway. In the 19th century there were important demographic changes and the population drew back from 1844 most likely due to the philloxera plague .

In 1848, according to Madoz, the streets of Almoster were in very poor conditions, the town had a natural spring of excellent water and there were some mines in the Puig d'en Cama. The only farming excedents were wine and hazelnut. The town counted with three oil mills but, he did not talk about the brick-field that, apparently, existed in 1445.

With the coming of the 20th century, the population started to decrease: 445 people in 1900, 385 in 1920 and 291 in 1950. In the last years the population experienced an important growth: 415 people in 1970 and 687 in 1997.

Nowadays the municipality is formed by four urban centres: Almoster, Puntarrons, Urbanització Picarany and Urbanització Castellmoster.

Town Festival of Sant Anton and Sant Senén. (July 30).

Town Festival of Sant Miquel. (September 29).

Oil Fair. (First Sunday in December).

Festivity of Sant Isidre. (May 15).

In town there are some old houses built with voussoirs such as Cal Victor and Cal Llombart (with beautiful Renaissance balconies).

The parish church from 1704 worships Sant Miquel Arcàngel has pure and simple lines.

The altarpiece dedicated to Sant Miquel Was destroyed, like the rest of altarpieces in the temple, was destroyed in 1936. Only a Baroque soffit dedicated to Sant Isidre was saved from the destruction. From the many old deserted farmhouses the most important are 'El mas de Carreras', 'mas Picarany' and 'el mas del Victor'. The latter belonged to Josep Rossell i Martí, businessman and major of Reus, who built a silk factory that was never inaugurated due to the September Revolution. In the outskirts of town there is a simple Calvary formed by three small chapels.

According to our town's tradition, the name of the Torrent de na Castella comes from the Castilian soldiers that died in 1714. The same name though, already appeared in some documents in 1520.

- Gran Geografía Comarcal de Catalunya

- Anguera, Pere.- "Història dels pobles del Baix Camp".
Almoster.- Suplement editat pel setmanari "Reus Diari", 1.989