Switzerland's top diplomat, Didier Burkhalter, has handed in his notice and will depart from the job at the end of October.
The Swiss foreign minister said in his resignation letter on Wednesday that it was time to write a new page in his life.
"I do not know yet what ink I will use for this, but I think it will have more personal colors and be less visible publicly," Burkhalter, who grew up in the French-speaking Western Swiss canton of Neuchâtel and has been a member of the Swiss cabinet since 2009, wrote in French.
At a news conference, organised at short notice, Burkhalter dismissed speculation that he was disappointed with the government or frustrated about increasing criticism in parliament over the handling of Swiss relations with the European Union.
"Criticism can be invigorating," he told a packed press conference in Bern on Wednesday.
He said his resignation would give a fresh impulse for talks on future ties with the EU - Switzerland's most important trading partner.
Relations with Brussels suffered a serious setback in 2014 when voters approved immigration curbs, temporarily blocking negotiations on a series of bilateral accords.
Burkhalter mentioned Switzerland's role as mediator in defusing the crisis in Ukraine in 2014 as one of the highlights of his career as foreign minister.
He has been head of the foreign ministry for five years and chaired the Organization for Security and Co-operation in Europe (OSCE) in 2014.
He also stressed the values of Switzerland and the role of Geneva as seat of numerous international organisations, including the United Nations.
"Switzerland can play in important role in the world," he said.
The 57-year old politician added that global politics has become more complex in recent years and it had notably become difficult to win international support to try to solve humanitarian crises.
Burkhalter looks back over a 30-year career as a politician both at the local, cantonal and national level.
He was first appointed to the government as interior minister in 2009 and as foreign minister from 2012 onward. Burkhalter also served as Swiss president in 2014, an office which is taken up by a different member of the seven-member cabinet in rotation each year.
He gave no hint about what he will do next apart from saying he and he wanted to be out of the public limelight.
Burkhalter is due to leave his foreign minister job at the end of October. On Thursday, following the announcement, his centre-right Radical Party announced it would open the nomination process, which will close in early August. Parliament will then elect his successor in the multi-party cabinet on September 20.
The party said the replacement should be a French- or Italian-speaker to ensure equal representation between the language regions in the seven-member cabinet.
It is widely thought that his centre-right Radical Party will be able to keep two seats beside the two members each of the leftwing Social Democrats and the rightwing Swiss People's Party as well as one seat for the centrist Christian Democrats. However, observers do not exclude a reshuffle of cabinet portfolios.