sentences:  Thus from the year 626 the executive bureau was headed by its two vice-directors, the "Shàngshūpúshè".Around this time, probably by Emperor Taizong's orders, the institution of multiple chancellors was formalized, with the heads of the executive, examination, and legislative (which was renamed the "Zhōngshūshěng" (中書省)) bureaus regarded as the chancellors.As there were often, but not always, more than one head for the examination and legislative bureaus, there were not necessarily only four chancellors.