Berton, MarcoMarcoBertonFOSCHINI, LUIGILUIGIFOSCHINICACCIANIGA, AlessandroAlessandroCACCIANIGACiroi, StefanoStefanoCiroiCongiu, EnricoEnricoCongiuCracco, ValentinaValentinaCraccoFrezzato, MicheleMicheleFrezzatoLA MURA, GIOVANNIGIOVANNILA MURARafanelli, PieroPieroRafanelli2020-08-272020-08-2720172296-987Xhttp://hdl.handle.net/20.500.12386/26899In recent years, the old paradigm according to which only high-mass black holes can launch powerful relativistic jets in active galactic nuclei (AGN) has begun to crumble. The discovery of γ-rays coming from narrow-line Seyfert 1 galaxies (NLS1s), usually considered young and growing AGN harboring a central black hole with mass typically lower than 10^8 M_☉, indicated that also these low-mass AGN can produce powerful relativistic jets. The search for parent population of γ-ray emitting NLS1s revealed their connection with compact steep-spectrum sources (CSS). In this proceeding we present a review of the current knowledge of these sources, we present the new important case of 3C 286, classified here for the fist time as NLS1, and we finally provide a tentative orientation based unification of NLS1s and CSS sources.ELETTRONICOenArticle10.3389/fspas.2017.000082-s2.0-85049224017000428535800001https://www.frontiersin.org/articles/10.3389/fspas.2017.00008/full2017FrASS...4....8BFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation