While working on his opera "Lucrezia" at the end of 1935, Respighi had become ill with a fever and fatigue. Subsequent medical checks in January 1936 revealed samples of "S. viridans" bacteria in his blood, leading to the diagnosis of subacute bacterial endocarditis, a heart infection still untreatable at the time and probably brought on by his recent throat infection and oral surgery. Respighi's health deteriorated over the next four months, during which he received three blood transfusions and experimental treatment with sulphonamides imported from Germany. Elsa made a conscious effort to hide the severity of the illness to others, except a select few. Respighi died on 18 April in Rome, aged 56, from complications of blood poisoning. Elsa and several friends were by his side. The funeral was held two days later. His body lay in state at Santa Maria del Popolo until the spring of 1937, when the remains were re-interred at the Certosa di Bologna, next to poet Giosuè Carducci. Inscribed on his tomb are his name and crosses; the dates of his birth and death are not given.