Maundy Thursday (also known as Holy Thursday, Covenant Thursday, Great and Holy Thursday, Sheer Thursday and Thursday of Mysteries) is the Christian feast, or holy day, falling on the Thursday before Easter. It commemorates the Maundy and Last Supper of Jesus Christ with the Apostles as described in the Canonical gospels.^[1] It is the fifth day of Holy Week, and is preceded by Spy Wednesday and followed by Good Friday.^[2]

The date is always between 19 March and 22 April inclusive, but these dates fall on different days depending on whether the Gregorian or Julian calendar is used liturgically. Eastern churches generally use the Julian calendar, and so celebrate this feast throughout the 21st century between 1 April and 5 May in the more commonly used Gregorian calendar. The liturgy held on the evening of Maundy Thursday initiates the Easter Triduum, the period which commemorates the passion, death, and resurrection of Christ; this period includes Good Friday, Holy Saturday, and ends on the evening of Easter.^[3][1] The mass or service of worship is normally celebrated in the evening, when Friday begins according to Jewish tradition, as the Last Supper was held on feast of Passover.^[4]

The Second Battle of Rivas occurred on 11 April 1856 between Costa Rican militia under General Mora and the Nicaraguan forces of William Walker. The lesser known First Battle of Rivas took place on 29 June 1855 between Walker's forces and the forces of the Chamorro government of Nicaragua.

At the time, a major trade route between New York City and San Francisco ran through southern Nicaragua. Ships from New York would enter the San Juan River from the Atlantic and sail across Lake Nicaragua. People and goods would then be transported by stagecoach over a narrow strip of land near the city of Rivas, before reaching the Pacific and being shipped to San Francisco. The commercial exploitation of this route had been attained from a previous Nicaraguan administration to Wall Street tycoon Cornelius Vanderbilt's Accessory Transit Company. Garrison and Morgan had wrested control of the company from Vanderbilt and then supported Walker's expedition. Vanderbilt spread rumors that the company was issuing stock illegally in order to depress its value, allowing him to regain controlling interest.