The definition of undeclared work only appeared in Czech legislation with the entry into force of the Employment Act (i.e. in 2004). Until then, even the previous legislation had paid attention to the performance of undeclared work, although it had not yet formulated it in this way. Already Act No. 1/1991 Coll., on Employment (hereinafter referred to as the “original Employment Act”) established the employer’s obligation to employ foreigners and stateless persons only if they had a residence permit and an employment permit.