It has long been observed that periods of intense seismic activity in a region alternate with periods of relative quiescence, but establishing whether this is the expected result of purely random fluctuations or is due to some broad-scale physical processes occurring in the Earth is a challenge. We present here compelling observations which show that periods of high seismicity rate and periods of quiescence are synchronized throughout the Anatolian plate. These observations are based on the remarkably similar evolution of the numerous seismic clusters between 2003 and 2017 in Anatolia. Two outside clocks set the timing of these activities, the 2004 M9.2 Sumatra earthquake and the 2008-2011 episode of slab rollback/deformation in the Hellenic subduction. The observed high seismicity rate in the plate which began with the Sumatra earthquake and lasted for about 7 years has been replaced by a relatively uniform quiescence period.