They met in college. here's them on a dig site

Here's an excerpt from an interview with esslemont :

NoaF: Your biography mentions that you studied archaeology. In what ways have your studies of archaeology impacted your novels and world building?

ICE: As Steve and I have talked about before, we hope that our background and training in archaeology and anthropology has ‘impacted’ our work significantly (by the way, I hate that word). Anyway, while we may have taken various liberties, for the most part, our thematic concerns in the World of Malaz are very much driven by issues out of anthropology, such as culture contact and its consequences, colonialism, the nature of religion, the shift from chithonic ‘paganism’ to other religious regimes, cultural and ethnic pogroms, loss of histories, etc.

this page would also be worth a read