Popular marijuana activist/writer Jack Herer, nicknamed the "Emperor of Hemp" and/or the "Hemperor," died Thursday (April 15) from complications of a September heart attack that he suffered after leaving the Hempstalk festival stage in Portland, according to OregonLive.com.

He was 70 years ago.

Since the heart attack, he had been recovering at his home in Eugene, Oregon.

Herer was a longtime marijuana activist and the author of the landmark book The Emperor Wears No Clothes: The Authoritative Historical Record of Cannabis and the Conspiracy Against Marijuana, which helped ignite the modern marijuana legalization movement. By 2004, the book had been through 16 printings and published more than 600,000 copies.

The veteran activist died just as the movement he has been supporting for nearly 40 years is beginning to gain momentum. He's been rallying to restore the hemp plant to American agriculture for decades.

Oregon and 13 other states, plus the District of Columbia now permit medical marijuana. Last fall, the Obama administration said it will not prosecute for possession in medical marijuana states. And now, in November, California residents will vote on a legalization initiative; while activists in Oregon and Washington are gathering signatures now for similar initiatives.

Herer is credited with advancing the marijuana movement, helping to bring its legalization to the point its at today. His influence on the weed culture is so big, he had a strain of marijuana named after him that won a Cannabis Cup in 1995.

He was born in New York City, and in the early 1960s, he moved his wife and family to Los Angeles. A short time later, he divorced but stayed close with his children. He married and divorced twice more before marrying Jeannie Hawkins in 2000.

At the age of 30, he smoked his first joint and fell in love. He had a sign business, which he left to open a head shop on Venice Beach, then made a lifelong friend in "Capt." Ed Adair, another head shop owner and a longtime marijuana advocate in Los Angeles.

In 1973, Adair and Herer pledged to campaign until marijuana was legal, everyone imprisoned for possession was freed, or they turned 84. Adair died in 1991 and Herer fought on.

In September, he attended Portland's Hempstalk, where he delivered a speech and shortly thereafter, suffered a heart attack. He survived. So, his wife rented a house in Eugene, where she cared for him until his death.

"I'm sad that it happened, but I'm glad that it happened in Eugene. Everyone has been wonderful to us here," Jeannie Herer told OregonLive.com.

Herer is survived by his wife, six children, a brother and a sister.

Funeral arrangements had not been completed at press time.

Herer used to copies of his popular book, The Emperor Wears No Clothes, from his website, but sales have been suspended since September. He posted half of it on his website at JackHerer.com. Or purchase your own copy over at Amazon.com from $33 and up.

In related news, Cypress Hill's B-Real and his alter-ego Dr. Greenthumb are putting on an event on May 8th in San Bernardino, Calfornia called the Spring Gathering, which consists of a concert and Medical Marijuana Expo. In additions to performances from Method Man & Redman and the Kottonmouth Kings, the Gathering will include keynote panels and discussions with speakers will talk about cannabis education, legal workshops and grow tips.

We are giving away a pair of tickets to the event, so click here to enter.