From a 1951 booklet:
The Indiana Capitol
Its Predecessors and Related Buildings
no author given
Published by the Indiana Historical Bureau in Indianapolis
Vincennes was the capital of Indiana Territory for the first thirteen years following the creation of the Territory, July 4, 1800. Territorial assemblies in the latter part of the period met in a stoutly constructed frame building, which then stood on the site of the present First Nation Bank Building. On the first floor were the offices of the government; on the second, the assembly room itself, reached by an outside stairway at the end of the building. Wooden pins held the framework of the structure together and an enormous lock with a key weighing half a pound protected official secrets.
Many years before it was removed from its first site, a porch and a lean-to were added, and it was used as a dwelling. In 1919 the Women's Fortnightly Club of Vincennes initiated a movement to purchase and restore the first Territorial Capitol. The purchase of the old building was accomplished, and it now stands in Harrison Park. In 1933 the work of restoration was completed, and the Territorial Assembly Hall and its surroundings are now a memorial of pioneer days well worth seeing.
In 1813 the capital of Indiana Territory was removed from Vincennes to Corydon. The stone courthouse which Dennis Pennington had contracted to build four years earlier was not yet finished and pending its completion the territorial assemblies met in temporary quarters. Possible use of the courthouse as a capitol was evidently considered in its planning. Pennington erected a forty-foot square, thick-walled, two-story building surmounted by a small tower. Stone flagging covered with sawdust formed the floor of the lower story. The rooms had high ceilings and there were big fireplaces on both floors.
During sessions of the legislature, the House of Representatives occupied the lower floor and the Senate, the upper. The Supreme Court Room was also on the second floor. Apparently the building was put to its primary use as a courthouse between sessions and after the removal of the capital from Corydon it reverted to that use. In 1917 the building was purchased by the State of Indiana as a "memorial to the pioneers who established the commonwealth of Indiana"; it continued to be used for county offices until a new courthouse was completed in 1927. During its long period of use by the county, many changes had been made in the external and internal features of the building. The restoration of the capitol to its original plan and design was carried out by the Department of Conservation, which now maintains it as a state memorial.