In a large saute pan, heat oil over medium heat. Cook onion and garlic in oil, stirring frequently, until transparent. Stir in cubed meat, and cook until browned. Stir in red bell pepper, bay leaf, cumin, and oregano; cook for 2 to 3 minutes.

Stir in sherry, tomato sauce, vinegar, olives, raisins, and capers. Pour in enough water to just cover meat. Bring to boil, reduce heat to low, and cover. Simmer until fork tender, about 1 1/2 hours. Add more water if the stew becomes too thick.

Stir potatoes into the stew. Season with salt and pepper to taste. Cook, covered, until potatoes are almost tender. Uncover, and cook until done.