Delft's city administration developed similarly to that of other cities granted charters by the Counts of Holland. The charters provided the broad outlines that each city fleshed out according to its traditions, circumstances, and budgets. In the early 1700's, Boitet described the top level of the process as it had had been conducted in Delft for two hundred years before Leeuwenhoek's time. Although it is called a constitution, it does the bare minimum, setting out the major offices and the process for changing who occupied them.

Boitet's Beschryving, page 131-132 (my translation and emphasis):

The whole Administration, consisting of Forty Members, has each year Five ordinary Meetings

the first being on the 16 December

(when that date comes on Sunday or Thursday, then the 17th) at which Meeting the New Members of the Gentlemen Forty (Veertigraad) are chosen for life, by majority of votes, to replace the deceased, etc.

The second ordinary Meeting is on 23 December

when by the whole Gentlemen Veertig, also by majority of votes, a  Orphan Master (Weesmeester) is appointed or continued for one year, also a Treasurer (Tresorier) for a term of six years, and also for a term of three years the gentlemen Delegates for this City to the Council of Delegates of Holland and to the Admirality at de Maze (Rotterdam).

The third Ordinary Meeting is on 30 December

when there are by majority of votes from the Gentlemen Forty a Nomination made of the Gentlemen of the Law (Heeren van de Weth), namely eight Gentlemen as Mayors (Burgemeesters), and fourteen as Magistrates (Schepenen).

The fourth Ordinary Meeting is on 31 December

when there by majority of votes, from the forenamed Nominees made the previous day, are elected four Gentlemen as Mayors, and seven as Magistrates: whose Administration begins on the following 1 January.

The fifth Ordinary Meeting is at the beginning of January

depending on the arbitrage of the Mayors on what day, in which Meeting by majority of votes are also appointed the incoming Orphan Masters, Harbor Masters (Havenmeesters), and delegates to the provincial council (adjuncts ten dagvaart).

Every three years by a majority of votes by the Gentlemen Forty, one of the Gentlemen for a term of three years is appointed as Chief-Officer (came to be called the Pensionary) of this City, whose Administration begins on the following 1 January.

In all of the Meetings not only do the Gentlemen Forty have a vote, but also the Gentlemen of the City Fathers (Vroedschap) who would be outside the Forty, although that has not happened for a long time: and would as members of the Forty recognize the Gentlemen who have been Mayor, Magistrate, Treasurer, Orphan- and Harbormaster.

All of the remaining Commissions, such as to the Meeting of the Council of State, the Auditors Room of Holland, the Admiralty in Zeeland, etc. are filled in the Mayors Room.

City Hall, pictured above, was rebuilt after a fire in 1618.