Relief from the Tomb of Horemheb; New Kingdom (Dyn. XVIII / Tutankhamun - Ay); Saqqara; Limestone; Inv. No. 2566; Franco-Tuscan Expedition 1828-1829
This remarkable relief was brought back to Florence from Egypt as part of the Franco-Tuscan expedition of Champollion and Rosellini (1828-1829).
Florence acquired approximately 2,000 objects during this trip through a combination of items purchased on the antiquities market and also archaeological excavations (division of finds).
So the question remains how do relief's from one tomb get dispersed in museums across the world?
Well it's a combination of factors, with some interplay of randomn events over the last couple of centuries. For example...
Antiquities dealers selling artefacts in Egypt during the 19th and 20th centuries
Foreign ambassador's to Egypt that acquired collections for their own countries (and themselves)
Division of finds from joint excavation's (e.g. France and Italy above)
Collections (private and public) that are eventually resold (e.g. von Bissing)
Countries splitting artefacts across several museums (e.g. Turin, Florence and Bologna)