Q: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
Passage: The creation of modern-day Eritrea is a result of the incorporation of independent, distinct kingdoms and sultanates (for example, Medri Bahri and the Sultanate of Aussa) eventually resulting in the formation of Italian Eritrea. In 1947 Eritrea became part of a federation with Ethiopia, the Federation of Ethiopia and Eritrea. Subsequent annexation into Ethiopia led to the Eritrean War of Independence, ending with Eritrean independence following a referendum in April 1993. Hostilities between Eritrea and Ethiopia persisted, leading to the EritreanEthiopian War of 19982000 and further skirmishes with both Djibouti and Ethiopia.
A:
In what year was the Sultanate of Aussa founded?