Pair are accused of misusing samples from a popular 1950s love ballad.

A copyright infringement trial over Jay Z’s 1999 hit ‘Big Pimpin” began in Los Angeles on Tuesday with both the rapper and producer Timbaland in attendance. A lawyer for the heirs of Egyptian composer Baligh Hamdi accused the pair of violating rights to Hamdi’s 1957 hit ‘Khosara Khosara’ in creating ‘Big Pimpin”.

Attorney Pete Ross accused Jay Z of lacing vulgar lyrics over Hamdi’s music without receiving the proper clearance. The lyrics are not an issue in this case, however, and representatives for Jay Z and Timbaland claim the pair secured the appropriate rights to sample ‘Khosara Khosara’ on the Vol. 3… single.

Timbaland’s attorney Christine Lepara told jurors that the producer initially sampled elements of Hamdi’s work thinking it was royalty-free, but he later secured the appropriate rights. Ross rejected that statement, accusing the pair of violating Hamdi’s “moral rights,” a legal concept he said is well-established in Egypt and would have required the pair to get permission to sample ‘Khosara Khosara’ in a song celebrating a promiscuous lifestyle.

Lepera denied “moral rights” were at issue in the case and said evidence would show that Hamdi’s heirs had been repeatedly paid for the sample. She also claimed ‘Big Pimpin” includes many elements that aren’t copyrightable.

The trial will resume on Wednesday with testimony from an expert on Egyptian music. [via Billboard]