The Christianization of the people of Guimaras started almost simultaneously with that Iloilo. For this purpose, the Spaniards organized the pueblositos or villages of Nayup with San Pedro Apostol as the patron saint and Igang whose patron saint was Santa Ana. For a long time, these small villages formed a “visita” of oton, Iloilo. The Governor at that time, General Dasmariñas reported to the king of Spain on June 20, 1551 and that one of the two friars of Oton was assigned to Guimaras who made his visits from time to time.

According to Don Pedro Armengol, an Ambassador of Spain wrote that a Spanish missionary may have named the island after a peninsula in Portugal called Guimaraes, or from names of places in Spain such as Guimaron in the provinces of Leon and Galerea, Gimenia in Catalonia, Gomera in the Canary Islands, and Guimaraon in another province.

In 1942, the island fell under the juriction of Dumangas until 1751 when the jurisdiction of Dumangas until 1751 when the Jesuits replaced the Augustinian Order. Then the Dominicians took over Guimaras. By 1755, it was organized into a regular parish. Finally, when the population had increased considerably, the island was given its municipal status with a seat of government at Tilad, now Buenavista. The old town site was in the place known today as Old Poblacion.

The American regime brought another faster progress to the island. In 1908, Guimarasnons were given the right to elect their municipal president. One great American left an indelible mark in the island, Douglas Mac Arthur, fresh from West Point as a Second Lieutenant at the age of 23, came to Iloilo as the head of the Company of Corps of Engineers. They constructed roads and the Sto. Rosario Wharf, presently name Mac Arthur’s Wharf, which are still in use today.

On the other hand, folklore says Guimaras, which was formerly known as Himal-us was named after the impetuous but ill-fated lovers, Princess, Guima and slave Aras, who defied tradition for their romance. Rejecting the betrothal by her father to anther nobleson, they escaped by a small raft but disappeared in the raging ses. From then on, whenever strong winds churned the seas, people seemed to here the echo of the lover’s names shouted by her repentant father, thus, the name Guimaras.

Guimaras first gained status as a Sub province of Iloilo by virtue of RA 4667, WHICH WAS ENACTED BY Congress on June 18, 1966. It was proclaimed as a regular and full-fledged province on May 22, 1992 after a plebebiscite was conducted to ratify the approval of its conversion pursuant to Section 462 of RA 7160. Shortly after Guimaras acquired provincial status, President Fidel V. Ramus appointed Emily Relucio – Lopez as its first Governor.

The Province of Guimaras was first made up of 3 municipalities. In 1995, by virtue of Republic Act No. 7896 and Republic Act No. 7897, the municipalities of Sibunag and San Lorenzo, respectively, were created in the Province of Guimaras. The two municipalities officially acquired their municipal status after May 8, 1995 plebiscite held simultaneously with the local election.