The present invention relates to workflow systems and methods. In one embodiment, the invention relates to integration of a calendar system with a workflow system where a calendar event can initiate a workflow by sending a message to a form route manager. The completion of a workflow or step in the workflow can result in sending a message to a calendar system to generate an event. In another embodiment, the invention relates to the integration of workflow with a project management system that includes project segments, which are processes that can be defined and controlled by workflow routes. The project management system sends a message to the workflow system to initiate workflow and the workflow system sends a message to the project management system, for example, at the completion of the workflow route. The relationship between the workflow routes can maintain the relationship between the project segments. If the relationships between project segments change, the relationship between the workflow routes changes without added effort.