I want to know the answer to the following question:
When did the Ming first request Tsongkhapa to come to court?
All the background I'm provided with is that "A. Tom Grunfeld says that Tsongkhapa claimed ill health in his refusal to appear at the Ming court, while Rossabi adds that Tsongkhapa cited the "length and arduousness of the journey" to China as another reason not to make an appearance.". Is that enough to answer the question?