When the Reformation in 1560 removed the Church from its ruling position in the city, the merchants and the craftsmen fought for control of its administration. The result was tension and confusion in the city which was only resolved when the Crown stepped in, leading to the Letter of Guildry being passed in 1605.
The Letter of Guildry regulated the city's craftsmen, through Trades House, and merchants, through Merchant's House. A Dean of Guild (a merchant) and a Deacon Convenor (a craftsman) were appointed to control the admittance of members to the guild. Membership of the guild was now a prerequisite for becoming a borough magistrate or town councillor. Effectively, the two Houses now controlled the government of the city. However, although James VI had stated that the two sections of the Guildry should be equally represented in council, several of the key positions (such as the Treasurer) were always drawn from the Merchants' House.
A list of eligible crafts of the Trades House was drawn up, which gradually evolved into the fourteen craft Incorporations of today: the hammer men (metalworkers), tailors, cordiners (leather goods), malt men, weavers, bakers, skinners, wrights (skilled carpenters), coopers, fleshers (tradesmen who provided meat for the city), masons, barbers and the incorporation of bonnet makers and dyers.
As the trading activities of the city blossomed in the eighteenth century, the Merchant's House became stronger with it, and it's superior position in the council allowed it to take more and more control over the city's direction. The House's activities included the establishment of the Glasgow Necropolis as a quality burial ground (opened 1833), influencing the building of the Forth and Clyde Canal, as well as pressuring the government for the establishment of a reliable postal service.
In 1833, the Scottish Reform Act was passed, and the guild's hold over the town council was at an end. Councillors and magistrates were now to be elected by all citizens - not just by other 'privileged citizens' as had been the case previously - and candidates no longer had to be merchants or craftsmen. Also, the Merchants' and Trades Houses were no longer considered one body under the Guildry (which had never really been the case in reality anyway).
In 1846, the right of the guilds to claim exclusive privilege over trading in Scottish burghs was abolished. In other parts of the country, incorporations split up their funds between their members and broke up their society. In Glasgow, however, the Trades House incorporations continued, focussing on activities for the benefit of members, families, and benevolent schemes for public welfare. Since then, the primary role of both Merchants' House and Trades House has been to raise funds, which are then employed for the benefit of members, their crafts, and to finance various charitable activities.