What did people think bad luck was caused by?

Religious Reasons

Explanation: The belief of the number 13 was cursed or bad luck. In the Middle Ages, there were 13 people in attendance at the "Last Supper" therefore it was believed that 13 people at the gathering was a bad omen. The reasoning for that is because, Judas was the first to get up from the table at the Last Supper and he was the one to kill Jesus,  it stood to reason that the first person to get up from a table of 13 would mean that person would have bad luck.

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"the sepoy rebellion was the result of many, many influences and stressors on the cultures of india living under british rule. in britain, it's called the sepoy mutiny on the indian mutiny, but in india, it's called the first war of independence.

the main reason is concerned to the british paramountcy , the belief in british   dominance in india political, economic and cultural life had been introduced in india about 1820."

"they were forced to grow crops that benefited the colonizing nations instead of feeding their own people."