The 'cycle' is a very important part of Colosseum. The day in Colosseum is broken in to a minimum of 6 four hour chunks of time. Each of these four hour chunks is called a cycle. Generally, the first cycle of each day starts one second after midnight local time. The six cycles per day are known as cycles A - F (although each cycle has a unique number that increments sequentially). Some activities in the city are only available for certain cycles. For example, an arena may only allow combat during cycles C, D and E (8:00:01am-12:00pm, 12:00:01pm - 4:00pm, 4:00:01pm - 8:00pm). Players should pay close attention to allowable actions by cycle.
All previously set actions occur as planned in this time frame, regardless of player connectivity. For example, a player can set up future actions for his or her servants in upcoming cycles. This allows the player to make action deadlines while off line or busy with other actions (e.g. navigating the library, searching for a document, chatting with other owners, etc.).
Each city has it's own sequence of cycles. In some cases, they may match other cities but in most, they'll be different. All city cycles do match up to empire cycles (as well as the master cycle, hidden from players).
When the game was initially developed, there was only the master cycle. This was always a problem during code development but we managed to make it work. While completing the combat code, we realized that it was getting too painful to work around the bad design. Cycles needed to be more granular - at the city and arena levels. We halted coding on any new work and went back to fix this issue. It required numerous changes in the data model and code but they are nearly complete now. We'll be heading back to the work plan for the next sets of new code this week.
For players playing in multiple cities, paying attention to multiple cycles is key to success.
An important note here. Cycles are predetermined slices of time for servant based actions. The player (acting as a citizen in the game world) operates at real time and can perform most actions as needed.
[Note: It is possible to have smaller and more plentiful cycles in a day. Tournaments and other special activities may change the cycle lengths as necessary.]