In 693, the metropolitan of Toledo, Sisebert, led a rebellion against Ergica in favor of raising a man named Suniefred to the throne. The rebels controlled Toledo for a time, because they were able mint coins in the potential usurper's name.[2] The plan to assassinate Ergica, the dowager queen Liuvigoto, and several main councillors failed, and Sisebert was defrocked and excommunicated. Furthermore, his descendants were barred from holding any offices and any other rebel or descendant of a rebel who might rise up against Ergica was to be sold into slavery.

In 694, Ergica enacted the most severe anti-Jewish law by a Visigothic king yet. In response, so he claimed to the Seventeenth Council of Toledo, to the connivance of Jews at home with Jews abroad who were fomenting rebellions to overthrow Christian leaders, Ergica declared all Jewish-held land forfeit, all Jews to be enslaved to Christians, and all Jewish children over the age of seven to be taken from their homes and raised as Christians. Jewish-owned Christian slaves were to be invested with the Jews property and to be responsible for paying the taxes on the Jews. In towns where Jews were deemed indispensable to the economy, however, this law wasn't applied. Indeed, as a result of the disintegrating Visigothic power, it was hardly enforced beyond the capital city itself.

Shortly before he died, Ergica amended a law which stated that anyone accused of theft of goods worth 300 solidi was to undergo a trial by boiling water. Under Ergica's changes, anyone accused of theft for whatever amount would have to undergo this ordeal. At the same time, Ergica published several laws which dealt harshly with the issue of fugitive slaves, while simultaneously rescinding laws which permitted slaveholders to mutilate their slaves as punishment. Ergica also remitted taxes, but this does not seem to have boosted his popularity. He got the bishops to order prayers to be said in his name and that of his family in every cathedral in Hispania.