[1] The reconstruction of the cathedral commenced during the early to mid-15th century during a time when Nantes and Brittany were commercially prosperous, initiating such large-scale architectural projects on a wide scale, partly owing to the opportunist and skilful diplomatic policy of John V, Duke of Brittany in a period of political turmoil and conflict with England.

The cathedral's foundation stone was laid on 14 April 1434, by John V, Duke of Brittany and Jean de Malestroit, Bishop of Nantes (1417–1443).

The arms of Duke John, who died in 1442, were placed in the staircase to the balcony, above the ducal portal, on the south side of the southern tower bay.

The triforium of the tower bay was constructed in an earlier and different style (Late Gothic Flamboyant, with a network of reticulated tracery) than the one of the nave proper.

The rest of the north transept and the choir, under the direction of St. Felix Seheult (city architect), were finished between 1840 and 1891, at a time of keen revival of the Catholic faith.

The long wait was also due to the fact that the former Romanesque church was standing right next to the city's protective walls, which had to be taken down before completing the choir, while destroying the remains of the previous cathedral as it was covered by the larger, new one.

[12] After the fire, a 39-year-old church volunteer, Emmanuel Abayisenga,[13] a Rwandan undocumented immigrant who had lived in France since 2012,[14] was detained for questioning but released without charge.

[16] On 9 August 2021, Abayisenga allegedly murdered 60-year-old priest Olivier Maire in Saint-Laurent-sur-Sèvre, and was again arrested after surrendering himself at a local police station.

[17] The French Bishops' Conference issued a statement, in which they stated “The author of this killing, who handed himself in to the gendarmes, was being sheltered by Fr Maire”.

The whiteness of the stone, accentuated by recent restoration work, the imposing dimensions of the nave and the aisles and the effect of the immense inner column create a Gothic atmosphere inside the cathedral.