Place the chicken in a pot and add the olive oil over medium heat.
Add the onion, garlic, bay leaf, salt and pepper and mix it with a spoon.
Add the vinegar and then add enough warm water to cover the chicken halfway (you can always add more later).
Simmer the chicken for about 45 minutes and then add the potatoes spreading among the pieces of chicken.
Continue to cook for another 15-20 minutes until potatoes are soft. You may need to add a bit more water, but do not add too much otherwise your sauce will be watery.
When potatoes are done add the lemon juice and oregano and mix well.
Serve with the sauce drizzled on top of meat and potatoes.