What is the ruling regarding prayers performed without ritual purity for ten years due to ignorance, not intentionally, and must they be redone after learning the ruling, and how are they to be calculated?

It is essential to mention what the person was ignorant of regarding the validity of their ablution, as it might not have affected its correctness. Otherwise, whoever performed an incomplete ablution, their prayer is invalid, even if done out of ignorance. This is because ignorance is not an excuse for neglecting purity according to the majority of scholars. Therefore, they must repeat all the prayers they performed with an incomplete ablution. However, Ibn Taymiyyah holds the view that whoever misses a condition or a pillar due to ignorance of the ruling is not required to repeat past prayers, but rather to repeat the prayer of the current time and adhere to it in the future.