SAN FRANCISCO — The elderly Texas billionaire who married Anna Nicole Smith in the last year of his life never intended to leave the former stripper any portion of his vast fortune, a federal appeals court ruled Friday.

The 9th U.S. Circuit Court of Appeals sided with a Houston jury that said J. Howard Marshall was mentally fit and under no undue pressure when he wrote a will leaving nearly all of his $1.6 billion estate to his son E. Pierce Marshall and nothing to Smith.

The ruling was the latest development in the bitter 15-year legal battle. Smith said the elder Marshall promised her more than $300 million, even though there was no documentation.

The fight between Smith and E. Pierce Marshall started in a sleepy Houston probate court and stretched all the way to the U.S. Supreme Court while outliving its two combatants.

Kent Richland, a lawyer for Smith’s estate vowed to appeal the latest ruling, possibly to the Supreme Court on different issues.

The decision – if it holds up – is bad news for Smith’s ex-boyfriend Larry Birkhead and their 3-year-old daughter Dannielynn. The child was named Smith’s heir in 2008 after she died of a drug overdose at 39 at a Florida hotel.

Birkhead and attorney Howard K. Stern were placed in charge of Smith’s estate. Neither returned calls seeking comment.

Stern and two other people have pleaded not guilty to charges of conspiring to provide thousands of prescription pills to the former model.

The convoluted dispute over J. Howard Marshall’s money has its roots in a Houston strip club where he met Smith. The two were wed in 1994 when he was 89 and she 26.

Marshall died the next year and his will left his estate to his son.

Smith challenged the will in a Houston probate court, alleging the billionaire’s son illegally coerced his father to exclude the former Playboy model from sharing the estate. She alleged that her husband promised to leave her more than $300 million above the $7 million in cash and gifts showered on her during their 14-month marriage.

While the probate case was pending in Houston, Smith filed for bankruptcy in Los Angeles, alleging in federal court filings that her husband promised her a large share of the estate.

In late 2000, the bankruptcy court awarded Smith $474.75 million, which a federal district court judge reduced to $89.5 million in 2002.

Between those two decisions, a jury in the Houston probate court ruled in March 2001 against Smith.

Since then, the two sides have been fighting over which court to obey.

Smith argued that the federal courts were in charge because the bankruptcy court was the first to rule.

Pierce Marshall countered the decision was the jurisdiction of the probate court, because that’s where the first legal action was filed and the site of the only full-blown trial.

On Friday, the unanimous three-judge panel said the bankruptcy court didn’t have the authority to decide a probate dispute and thus its $474.75 million award was only an advisory opinion.

The appeals court also said U.S. District Court Judge David Carter should have relied on the probate jury’s decision against Smith and tossed the case entirely.