The Origins of the Company
The full title of the Drapers' Company is "The Master and Wardens and Brethren and Sisters of the Guild or Fraternity of the Blessed Mary the Virgin of the Mystery of Drapers of the City of London". The word Mystery comes from the Latin “misterium” meaning professional skill. 
The Origins of Guilds
Early guilds or companies of the City of London acted as mutual protection societies providing a fraternity for their members and the trading aspects were not at first apparent. They had no common meeting house, and usually gathered in a neighbouring church, monastery or hospital, whose saint they adopted as patron. In the 14th century, they began to obtain Charters from the Crown, which gave them formal constitutions and rights to hold property, and defined their duties and responsibilities.
The Foundation of the Drapers’ Company
The first Royal Charter granted to the Drapers is dated 1364 and the records cite a date of 1361 for the fraternity’s foundation, although records show that an informal association of drapers existed as early as 1180. 

A Brotherhood of Drapers, a religious fraternity attached to the church of St Mary Bethlehem in Bishopsgate, is also known to have existed in the 1360s. It was founded in honour of St Mary by the ‘good people Drapers of Cornhill and other good men and women’.

The location of St Mary can hardly have been convenient for the majority of Drapers who lived in and around Cornhill, Candlewick Street (now Cannon Street) and Chepe (Cheapside). It may have been for this reason that allegiance was transferred to St Mary le Bow in Cheapside and later to St Michael’s Cornhill, where the Company continues to worship today. The Company has retained the Blessed Virgin Mary as patron saint.
In 1438 the guild received its Charter of Incorporation recognizing the Drapers as a legal corporate fraternity, with perpetual succession and a Common seal. Over the centuries the original privileges granted by Royal Charter have been confirmed and amended by successive monarchs.

The governing Charter of today is that granted by James I in 1607, amended by five Supplemental Charters, the most recent of which was granted in 2008.