The humanitarian crisis caused by Hurricane Maria has cast a spotlight on Puerto Rico and revealed how little many Americans know about the Caribbean island. A recent poll suggests that as many as half of all Americans are unaware that Puerto Ricans are US citizens. Here is a primer about Puerto Rican history.

‘Rich Port’

The indigenous Taino were the principal inhabitants when Christopher Columbus arrived in 1493. He originally called the island San Juan Bautista but it soon was known as Puerto Rico, or “rich port.’’ The United States conquered the island during the Spanish-American War and it became a US territory. In 1901, a series of legal opinions known as the Insular Cases argued that the US Constitution should not apply to Puerto Rico and other territories ceded by the Spanish because they were full of “alien races.’’ It wasn’t until 1917 that Puerto Ricans became American citizens under the Jones-Shafroth act — just in time for them to fight for the United States during World War I.

Economic struggles

President Trump was quick to cite the island’s economic woes in a recent series of tweets. Puerto Rico has been in a recession since 2006. It ran out of cash in 2016 after successive governments dug it deeper into debt by borrowing from Wall Street hedge funds. The US territory now has nearly $70 billion in debt, an unemployment rate 2.5 times the US average, and a 45 percent poverty rate.

No US voting rights

To this day, Puerto Ricans on the island are still unable to vote for president or elect voting senators or representatives to the US Congress. Like the other US territories, Puerto Ricans are only able to elect a nonvoting resident commissioner to the US House of Representatives. Just a few months before Hurricane Maria, Puerto Rican citizens had voted in favor of a referendum for statehood. Unfortunately, the only people who can incorporate the islands into a state are the voting members of Congress.

Deadly hurricanes are rare

Despite its location, Puerto Rico experiences a tropical storm on average every five years, and hurricanes are even more rare. Hurricane Maria was a Category 4 hurricane when it hit the island. The only Category 5 hurricane to strike it since 1851 was the San Felipe Segundo hurricane in 1928, which took the lives of more than 300 people.

Sophia Eppolito can be reached at sophia.eppolito@globe.com.