Final answer:
The query appears to be based on conceptual elements of Mesoamerican cosmology rather than a historical fact. It reflects the complex vertical and horizontal division of the universe in Mesoamerican beliefs, with Xibalba being the underworld.
Step-by-step explanation:
The question does not correspond to a specific historical figure or a widely acknowledged theory involving the stitching together of the middle world and Xibalba. However, it involves Mesoamerican cosmology, wherein civilizations like the Maya believed in a vertical and horizontal division of the universe, with Xibalba being the underworld. No single individual or deity was credited with a theory to 'stitch' these planes together; rather, these concepts are integral to the respective mythologies and religious beliefs.
In Mesoamerican cosmology, particularly within the Maya civilization, the cosmos was perceived through a complex system of vertical and horizontal dimensions. Xibalba was known as the underworld, ruled by death gods, and contrasted with celestial realms and the terrestrial, or middle world, where humans resided. Symbols and diagrams such as those found in the Borgia Codex and the Codex Féjervary-Mayer visually represent these ideas, depicting deities associated with these realms and their interconnectedness.
In conclusion, the question seems to derive from a mixed understanding of Mesoamerican beliefs, rather than a factual historical account or specific individual's theory. It is more aligned with the general concept of the universe's structure as interpreted and depicted by ancient Mesoamerican cultures in their codices and artwork.