Nelson Mandela has spent his first night in almost three months at his home in Johannesburg after being discharged from hospital in Pretoria.The former South African president, 95, was admitted in early June for a recurring lung infection.Family members have spoken of their happiness at having Mr Mandela home again for the first time since 8 June.However the South African government has said his condition remains critical and can sometimes be unstable.Mr Mandela returned home by ambulance early on Sunday and would continue to receive intensive care there, a statement from the South African presidency said.His suburban house in the suburb of Houghton has been "reconfigured" for his care.However, the presidency said he would be readmitted to hospital should his condition warrant it.The BBC's Mike Wooldridge in Johannesburg says all this seems designed to reassure not just the Mandela family but the nation, too, that he should be no more vulnerable when his condition is unstable than he was in hospital in Pretoria. Fortitude and graceThe Nobel Peace Prize laureate is revered around the world for leading the fight against white minority rule and preaching reconciliation with the white community despite being imprisoned for 27 years.Despite his various illnesses, the statement from Mr Zuma's office notes, the former president displayed "immense grace and fortitude".The South African government has released few details about his condition, appealing for Mr Mandela's privacy and dignity to be respected.The BBC's Andrew Harding in South Africa says this is not the discharge of a man who has made a significant recovery but the transfer of a patient from an intensive care ward in a hospital to a specially-built intensive care unit in his own home, presumably in line with his family's wishes.But he notes that some people will take encouragement from the fact that his doctors have said he was fit enough to make the 55km-journey (34 miles) and says such a decision will not have been taken lightly."It is a day of celebration for us, that he is finally back home with us," said his grandson, Mandla Mandela.Mr Mandela's lung condition is said to result from the tuberculosis he contracted during the 27 years he spent in prison for taking up arms against white minority rule.He has been admitted to hospital four times in the past year and his latest stay lasted 84 days.He became president after 1994 elections - the first time black South Africans were allowed to vote - and he stepped down five years later.