The timing of the prince’s meetings with other family members, especially the queen, is also likely to draw scrutiny. On March 10, Charles sat across a table from Prince Albert II of Monaco, who nine days later tested positive for the coronavirus. On March 12, officials said Charles had his last meeting with Queen Elizabeth after an investiture ceremony.

Medical advisers, they said, estimated that the earliest date the prince could have been infectious was the day after that, March 13, though it was not clear how they had arrived at that assessment. The palace declined to identify the members of Charles’s medical team or to discuss his prognosis in detail.

The incubation period for the coronavirus varies by patient, according to the World Health Organization, with most people showing symptoms about five days from the date they were infected. But it can incubate for as long as 14 days, which, given when Charles began showing symptoms, would be before he met with his mother.

“It is not possible to ascertain from whom the prince caught the virus owing to the high number of engagements he carried out in his public role during recent weeks,” the palace said in its statement.

In addition to public meetings, officials said Charles had been in contact with employees of the Duchy of Cornwall, his hereditary estate, and staff members at Highgrove House, his country residence in Gloucestershire. After suspending his public schedule on March 12, an official said, Charles stayed at Highgrove until Sunday, when he traveled to the more remote Birkhall.

The prince’s decision to travel even after experiencing symptoms, which the government has strongly discouraged, also raised questions. Officials at the palace said the symptoms were not pronounced enough to cancel his plans, and that Charles decided to go after consulting his medical team.

On March 16, the government advised people over age 70 to avoid nonessential social contact for 12 weeks. A few days later, the queen canceled her schedule and left Buckingham Palace for Windsor, where officials said she would be exposed to fewer people. She was joined there by Philip, who lives in retirement on the grounds of another royal house, Sandringham.