Pupils, parents and staff of Ysgol Gyfun Rhydfelen took their protest over a council decision to rename their historic school to the Senedd in Cardiff this week.
But Rhondda Cynon Taf council remains adamant about the change, saying the school's name must reflect its new location at Garth Olwg in Church Village, near Pontypridd.
Phil Ellis, Rhydfelen's deputy head, said: "The school is iconic. When it opened in 1962, the catchment area stretched from Maesteg to Newport, and up into the northern part of the valleys.
"There are now 11 Welsh-medium schools in the original catchment area. The heads of any of those schools would say the reason why this type of education has made such progress is the success of Rhydfelen. It's got that 'mother school' role."
Pupils will get an extra week's summer holiday as the school is packed up and moved to its new state-of-the-art home on the pound;30 million learning campus at Garth Olwg, which also includes a primary school and early-years centre. A third of Rhydfelen's current accommodation, in the village of Rhydyfelin, near Pontypridd, consists of temporary classrooms and wooden buildings dating back to 1918.
"We couldn't get better facilities," said Mr Ellis about the new site. "But the name is our heritage and we're proud of it. In Wales, we are a brand name and we don't want to just throw that away."
Sixth-former Seren Evans, 17, from Porth, said: "There is a lot of history with the name. To see it go will be heartbreaking. How can they be allowed to take it away?"
But council leader Russell Roberts said cabinet members had fully considered the views of parents, teachers and pupils, as well as local residents, in coming to its decision.
He said: "The new facility will need to be an integral part of the local community it will serve and this can only be achieved if its name reflects its location."