The two letters patent supplementing the edict granted the Protestants safe havens ("places de sûreté"), which were military strongholds such as La Rochelle, in support of which the king paid 180,000 écus a year, along with a further 150 emergency forts ("places de refuge"), to be maintained at the Huguenots' own expense. Such an act of toleration was unusual in Western Europe, where standard practice forced subjects to follow the religion of their ruler under the application of the principle of "cuius regio, eius religio".