Westminster Abbey (more properly the Collegiate Church of St.Peter, Westminster) is the major Christian church in London, after the Cathedral of St.Paul, and has for centuries been the coronation site for monarchs of England as well, frequently, as their burial place.
The Abbey at is built upon what was once an island – Thorney Island – amidst a marshy area west of the City of London. The island was at one time flanked by two channels of the Tyburn River, which have since been overbuilt.
There may have been a Christian church on Thorney Island as early as 604 CE, just eight years after the first Christian mission under St Augustine landed near Canterbury in 596 CE. Supposedly a fisherman in the river saw a vision of St.Peter, hence the dedication.
In that same year of 604, Ethelbert, uncle of the king of the East Saxons, founded St Paul's in the City of London, and that king, Serbert, is supposed to have founded the church formally in 616 CE . Thorney was thus the western minster in the area and it gained influence as the sea traders who came up the Thames moved further west along the riverbank, founding the settlement of Aldwych along the Strand (or shoreline).
Later royals chose to patronise the shrine; King Edgar (957-75) gave land for a church, and several kings, including Canute and Ethelred, donated relics. St Dunstan endowed a place for a dozen monks in 960 CE. Later, Edward the Confessor (1042-1066) had a vision of an ecclesiastic-royal complex including a palace with a large monastery and an abbey church suitable for royal functions and burials.
Devout though Edward certainly was, he was also driven by guilt in his building project. Earlier in his reign he had been forced to flee from a Danish invasion into exile in Normandy. He made a solemn vow that if he ever regained his throne he would make a pilgrimage to Rome in gratitude. Eventually he was able to oust the Danes (in the form of Canute and his son Hardicanute) and regain the throne, but the politically uncertain climate, with various Scandinavian powers still conceiving that they had the right to the English throne) made it unwise for him to leave for Rome. Pope Leo, being an understanding sort, excused Edward from his vow – on the condition that the king re-endow the monastery of Westminster.
Edward rebuilt the old Saxon church in the new Romanesque style and began a palace nearby. The work was consecrated on December 28, 1065, but Edward himself lived only another eight days. Harold Godwinson followed him as king, and he is believed to have begun the tradition of royal coronations in the Abbey. Certainly Harold's successor, William the Conqueror, was crowned here, on December 25, 1066, as were all successive period monarchs (except Edward V).
The first great contributor to the abbey in the Middle Ages was Henry III. The abbey of today is largely Henry's work, although at the time few of his subjects appreciated his efforts, because Henry diverted huge amounts of money meant for running the kingdom into his building plans at Westminster. In 1245 Henry began rebuilding the entire church in the Gothic style, intending it as a shrine to the memory of Edward the Confessor, whom Henry idolized.
The rebuilding of the eastern end of the abbey took just 14 years to complete. By the time Henry III died in 1272, becoming the first king to be buried in the Abbey, the choir and 5 bays of the 103 foot high nave were finished, but there the work halted for a full century. It took until 1532 before the abbey, apart from the West Towers, was finished.
However, the monks of Westminster had little time to enjoy their finally completed church. When Henry VIII began his Dissolution of the Monasteries the rich prize of Westminster (by then it owned over 200 manors up and down England) was one of the first to catch his eye. The Abbey was taken over by the crown in 1534 and closed in 1540. The church then was briefly a cathedral. It was during this time of turmoil that Westminster played its part in the creation of the expression "robbing Peter to pay Paul", when money meant for the abbey (dedicated to St. Peter) was diverted to the coffers of St. Paul's Cathedral.
Catholic Queen Mary I restored the monks at Westminster, but her successor Elizabeth quickly reversed that decision when she became monarch, and it was under Elizabeth that Westminster assumed its present role, as, in effect, the monarch's own church.
At different times the Abbey has held the royal ledgers, the treasury, and the royal regalia, whilst beside it the Palace of Westminster became, as well as the King's formal residence and the centre for his courts of justice, also the usual convening place for the English Parliament.