Plaid Cymru have held their first conference since becoming part of the executive governing Wales nine months ago.
Assembly member Alun Ffred Jones said their period in office proved Plaid was more than a party of protest.
Jones told the BBC that the party has "taken a step forward by taking on the responsibility of being in government".
It is the first time the party has held its annual gathering in Newport - traditionally a strongly Labour and Anglophone city.
Deputy first minister and party leader Ieuan Wyn Jones said he was celebrating achievements in office and looking forward to what the party wants to achieve over the next few years.
Launching Plaid's local election manifesto Llanelli AM Helen Mary Jones said: "As a party of government it is more important than ever that we, as a party, continue to drive forward the political agenda in Wales by composing new and exciting policies.
"We are determined not to fall into the trap that other governing parties have suffered, by becoming more concerned about preserving power rather than delivering change."